Vice President George Bush, in a decision that stunned Republican political strategists and some of his own supporters, Tuesday selected Dan Quayle, a relatively unknown 41-year-old junior senator from Indiana, as his vice presidential running mate.

In naming the staunchly conservative Quayle, scion of a rich and powerful family in a traditionally Republican state, Bush passed over a flock of better-known contenders who might have provided the ticket with greater experience, broader credentials and perhaps more political clout.

Yet Bush, who will accept the Republican presidential nomination at Thursday’s closing session of the GOP convention here, called Quayle “a dynamic young leader for the future of our party, the future of our nation.”

And President Reagan, who learned of the Quayle choice when Bush whispered it to him as the chief executive boarded Air Force One to leave for California on Tuesday afternoon, called it “an outstanding selection.”

Bush and his strategists argued that Quayle’s youth would attract baby-boom voters, his political philosophy would please conservatives, his Midwestern base would help with voters in critical neighboring states, his generally careful delivery would keep him out of trouble and his record of running well among women voters would help Bush with his worrisome gender gap.

Other strategists, however, including some delegates and some officials in his own party, worried that Quayle was not well-known outside his state, that Indiana offered only 12 electoral votes, which would almost certainly have gone to Bush anyway, that Quayle’s political experience was limited and that his support would be confined to those whose philosophy matched his own.

Telephones Others

Before naming his choice in a surprise announcement as he arrived here for the Republican National Convention, Bush telephoned others he had been considering for the vice presidential candidacy. Some, including California Gov. George Deukmejian, had told him earlier that they were not interested in the job.

Bush told Sen. Bob Dole of Kansas, the Senate minority leader, that he was one of two finalists, the senator’s spokesman, Walt Riker, said. “You can’t go too wrong picking someone from the Midwest,” Dole said later. “I’ve got a pretty good job now. Just give me five more senators, and I’ll run the country from Congress.”

Dole’s wife, Elizabeth, another contender, said Bush had called her too and told her she would not be on the ticket.

Still another contender, Rep. Jack Kemp of New York, said Bush had telephoned him to say that “it was a very close call.”

“ ‘Mr. Vice President,’ ” Kemp told reporters he replied, “ ‘I want you to know my support is unconditional.’ ”

Reagan also gave Quayle an enthusiastic endorsement:

“Dan was first elected to the Senate as part of the Reagan-Bush team in 1980,” the President declared in a prepared statement. “He’s a proven vote-getter. I’ve worked closely with Dan on a number of issues. He has been a leader in the Senate for a strong national defense, particularly the Strategic Defense Initiative, and proponent of innovative job-creation programs.

“His talent, intellect, family and energy will be valuable assets.”

Liked by Women

Bush strategists said that the blond Quayle, sometimes described as a Robert Redford look-alike, would bring glamour to the ticket. Secretary of the Treasury James A. Baker III, who becomes Bush’s campaign chairman Thursday, said polls show that Quayle does well among women and that he will help close the gender gap.

Quayle is a member of the baby-boom generation, which is coming into full political strength. As a point of possible appeal to those voters, GOP strategists suggested that Quayle offers a strikingly favorable physical contrast to 67-year-old Sen. Lloyd Bentsen of Texas, the Democratic vice presidential nominee.

The selection also appeared to be acceptable to the Republican Party’s right wing, even though Quayle has not always strictly hewed to the conservative agenda on social issues. Sen. Gordon J. Humphrey of New Hampshire, who had said he would oppose anyone who did not measure up to his conservatism, was lavish in his praise of the ticket.

“I’m thrilled,” Humphrey declared. “I couldn’t be more pleased. I’m excited.”

‘Tremendous Choice’

Religious broadcaster Pat Robertson, who had campaigned against Bush for the presidential nomination, called Quayle “a tremendous choice.”

Another factor weighing heavily in Quayle’s favor, sources said, was that in his Senate races he has been advised by both Robert S. Teeter and Roger Ailes, senior advisers to Bush. Moreover, the sources said, another Bush confidant, Treasury Secretary nominee Nicholas F. Brady, was high on Quayle.

In Indiana, however, political figures were surprised that Quayle was even in the running to be on the ticket and in fact thought he probably was preparing to retire from politics in a few years to run the Pulliam newspapers.

At a breakfast session here Tuesday, Indianapolis Mayor William H. Hudnut III told companions he did not expect Quayle to run for reelection to the Senate because he probably would be taking over the family newspaper empire.

Cites Family Life

Quayle himself had told reporters early this week that if he could choose his time to run for national office, he would not pick now. With three children less than 15 years old, he said, he worried about the intrusions of such a campaign on family life. He said his wife also has reservations about this.

But he added at the time: “If George Bush thinks I can offer the most to the ticket . . . Dan Quayle will sign up immediately.”

Bush and his party had just disembarked from the stern-wheeler Natchez on the banks of the Mississippi River and he was midway through his arrival speech when he announced that he had chosen Quayle.

A combination of cheers and moans erupted in the crowd, which included a large contingent of Kemp supporters.

National Security

In a short-sleeved, open-collar shirt and sweating in the hot, muggy weather, the vice president called Quayle “a leader in matters of national security” and a leader in “the effort to retrain our workers in this country so that they will be able to better lead the work force of tomorrow. . . .”

As Quayle mounted the platform and waved, Bush added: “Let me just say one or two more things. Dan Quayle understands how precious freedom is, and in the Senate of the United States he has been freedom’s friend. He is a family man with a loving wife and three beautiful children. Dan Quayle is a man of the future–a young man. A young man, born in the middle of this century, and from the middle of America.”

Exuberantly, Quayle kissed Mrs. Bush, wiped off her lipstick, grabbed the vice president by the arm and opened his brief remarks with a quip:

“Actually, I was just in the area and decided to stop by.”

‘Go Get ‘em’

Turning to Bush, he added: “I just want to thank you, first, for the confidence you’ve placed in me. As I was standing in that audience out there, a young man turned to me, named Steve Shambaugh from Orlando, Fla., and I sort of whispered to him that I was perhaps going to be the next vice presidential nominee. And you know what he told me? He said when you get up there, he says, ‘You tell George Bush one thing–go get ‘em!’ ”

Shouting and gesturing with both hands as he spoke, Quayle declared: “As we stand before you here, we are obviously honored, we are obviously a bit humble. But George Bush’s America believes and has the commitment to the American family that is so important to us all. George Bush’s America understands the problems that confront us and would lead us to the future and the 21st Century.”

Quayle, who was editor and associate publisher of the Huntington, Ind., Herald Press, a family-owned newspaper in the mid-1970s, is the grandson of the late Eugene Pulliam, a conservative owner and publisher of Indiana and Arizona newspapers.

Not in Close Circle

Despite his relationship with several Bush advisers, the senator’s background had not placed him in Bush’s close circle of friends.

Although Quayle’s press secretary, Jeff Nesbit, said the senator often stopped by Bush’s office to chat, the two men apparently have not had a close relationship. One longtime Bush aide, saying he knew of no relationship between the two men, called the selection of Quayle “quite odd.”

Only time will tell, this aide said, whether the young senator can withstand the test of a national campaign.

‘Doesn’t Stack Up’

Norman J. Ornstein, a political analyst with the American Enterprise Institute who specializes in Congress, declared he was “stunned” by the selection. “I didn’t think Quayle was a serious possibility and I don’t think he should have been a serious possibility. If you take any of the criteria–winning electoral votes, a signal of change, depth of experience and responsibility–he doesn’t stack up,” Ornstein said.

“I wouldn’t call him one of the 25 worst senators, but he’s certainly not in the top 25.”

A veteran Democratic political figure in Indiana, who declined to be identified, said he has followed Quayle’s career closely–and “to think that he might be a heartbeat away from the presidency is scary. He just doesn’t have the stature or the experience.”

Charge Weakness

The Michael S. Dukakis campaign lost no time in attacking the choice, suggesting that Quayle lacked qualifications for the job and that Bush showed weakness in picking him.

“We have learned two things about George Bush today: He can’t keep a secret and he couldn’t stand up to the pressure from the right wing of the Republican Party,” Dukakis campaign manager Susan Estrich said in a statement.

And former Democratic Rep. Floyd Fithian of Indiana, interviewed on ABC’s “Nightline” program, said the comparison between Bentsen and Quayle was between “a major heavyweight” and “a bit player.”

On the other hand, California’s Sen. Pete Wilson, a close friend of Quayle, called him “an inspired choice.”

“He will bring a great deal of youth, energy and substance to the ticket,” Wilson said. “I see him as a very intelligent, articulate conservative.”

‘Energetic as Hell’

And Keith Bulen, an Indianapolis attorney and former Republican national committeeman, called Quayle as “energetic as hell” and said he would not hesitate to carry the attack to the Democratic ticket.

“He’s a ferocious campaigner, although he can be a little shrill at times,” Bulen said.

Quayle ran an aggressive campaign in 1980 in unseating four-term Democratic Sen. Birch Bayh. Bayh ran campaign ads accusing him of raising large amounts of campaign funds from oil interests in Texas.

Pretty Lobbyist

In 1981, the press reported that Quayle and two congressmen–Tom Evans of Delaware and Tom Railsback of Illinois–had spent time in a townhouse in Palm Beach, Fla., with Paula Parkinson, a pretty lobbyist who later posed nude in Playboy magazine.

At the time, Quayle said he had roomed with another man in the townhouse. In September, 1981, the Justice Department reported it had uncovered no evidence that any member of Congress had swapped votes for sexual favors or other inducements by lobbyist Parkinson.

There was some skepticism on the convention floor about Bush’s vice presidential choice.

Jullie Gallaher, a Bush delegate from San Jose, said: “If it was my pick, well, I’d pick somebody else. I would pick someone more centrist.”

But Gallaher, a travel agent, added that ultimately she trusts Bush’s judgment.

‘A Little Puzzled’

California Republican Chairman Bob Naylor said of Quayle’s selection: “Well, it’s a good thing he came on so strong out there when Bush introduced him, because that impressed our people, many of whom had no idea who he was and were a little puzzled.”

Naylor added that he “puzzled” over the choice himself and decided that he thought it “could turn out to be a brilliant move.

“It really is a generational choice.”

Some women delegates knew so little about Quayle that they had no opinion of him. Others, such as Shirley Royer of San Mateo County, wife of former Rep. Bill Royer, leaned on the opinions of their husbands.

‘Glowing Terms’

“My husband knew him in Congress,” Shirley Royer said, “and told me that he (Quayle) was going to have a lot of appeal. He always talked of him in glowing terms. He will bring a lot of good experience and a lot of exuberance.”

Mary Ann Budak, an Indiana delegate, traveled from one state delegation to another on the convention floor answering questions about Quayle.

At Hawaii, Marilyn Harrison clutched her hand. “I just saw him tonight,” Harrison said, “and I think he’s great!”

When asked if the attraction was his looks, she said: “He is cute, but that’s not my thing. He sounded so strong and sure–such authority!”

Gets a Grilling

At the Washington delegation, where 40 of the 41 delegates were pledged to Robertson and were fierce right-to-life advocates, Budak got a grilling.

“What’s his family?” asked Marilyn Derby.

“Well, his family owns a newspaper . . .” Budak began.

“Wife? Children?” Derby asked.

“Yes, married, three children, two boys and a girl.”

“How does he feel about home education?” Wade Lachman asked sharply.

“I really haven’t heard his views on that.”

Conservatives Happy

Many conservative delegates were unhesitatingly happy with the choice, though.

Rep. Robert K. Dornan of Fullerton, generally thought of as the most conservative member of the California congressional delegation, said: “Dan Quayle is to the right of me and Kemp, and we’re a tad to the right of George Bush.”

He said he did not expect Quayle to help the Bush campaign much in California because Quayle is not known there. “Anyway,” Dornan said, “he will be needed in the Midwest, where he will be more effective.”

Dornan called it “stupid and condescending to women” to imply that Quayle’s youth and good looks would enlist female support. “Women voted for Nixon instead of Kennedy, who was much more handsome,” he said, referring to the 1960 race between Richard M. Nixon and John F. Kennedy.

‘Fantastic Choice’

Pamela Bell, a schoolteacher from Camden, Ark., who was attracted to politics by Pat Robertson, called Quayle “a fantastic choice.”

“I predict,” she said, “that he will help Bush appeal to women in their 30s and 40s who are worried about passing along the right values to their children.”

Sen. John McCain of Arizona said of Quayle: “He brings a different generation to the ticket, an independent knowledge of defense issues . . . and that is perceived as one of Dukakis’ major weaknesses.

“He is extremely telegenic. In the Midwest, he would make a significant impact.”

Initially Disappointed

A black delegate, Mary Lee Gray, senior deputy to Los Angeles County Supervisor Deane Dana, said she thought a number of members of the California delegation were initially disappointed in the selection of Quayle.

But she described herself as “very impressed” with him.

“I know him because his name is closely associated with the job training and partnership act which replaced CETA,” she said. “It involved the private sector in the creation of new jobs. That tells me he is very interested in addressing social issues.

“More important, by selecting an unknown, George Bush is indicating he is very confident. He could have picked a Dole. The ticket would have been a 50-50 sort of sharing. This (selection of Quayle) shows he (Bush) wants to be the head of the ticket, and it says he is confident he can carry the ticket.”

Staff writers John Balzar, Frank Clifford, Cathleen Decker, James Gerstenzang, David Lauter, Keith Love, Claudia Luther, Patt Morrison, Tom Rosenstiel, Robert Scheer, Bob Secter and Henry Weinstein contributed to this story.