Democrats have unified with remarkable speed behind Vice President Kamala Harris as she has taken over the top of the party’s ticket heading into the November presidential election.

It may be another story when it comes to a running mate.

As Pennsylvania Gov. Josh Shapiro and Arizona Sen. Mark Kelly have emerged as among the potential finalists, both have faced criticism from some organizations and activists who might otherwise be supportive of Democratic causes.

Harris’ team says she is interviewing six possible choices over the weekend before an announcement expected Monday. The next day, she and her running mate will appear together at a rally in Philadelphia, then visit six more swing states.

In addition to Shapiro and Kelly, Harris is said to be considering Minnesota Gov. Tim Walz, Illinois Gov. J.B. Pritzker and Gov. Andy Beshear of Kentucky and Transportation Secretary Pete Buttigieg.

Some congressional Democrats have promoted Kelly, a former Navy pilot and astronaut whose state has more than 370 miles of border with Mexico. They say his selection could help defuse attacks by the Republican nominee, former President Trump, who argues that Biden administration’s immigration policies are too relaxed.

Shapiro has high-profile supporters, too, including Philadelphia Mayor Cherelle Parker. She caused a stir by posting a video Friday depicting several Philadelphia-area officials and Democrats promoting Harris, but also playing up Shapiro as her running mate — appearing to suggest that the mayor had inside knowledge about Harris’ decision.

But a person with knowledge of the mayor’s thinking said the video was simply a case of Parker showing support for both Harris and the potential that Shapiro, Parker’s friend, would be the vice presidential pick. The person was not authorized to discuss the matter publicly and spoke on the condition of anonymity.

Both Kelly and Shapiro have also seen their detractors become more vocal as Harris’ closes in on a decision.

While that may not ultimately sway Harris, it is an indication that the honeymoon period, where the distinct wings of the Democratic Party coalesced behind her, may be ending in the less than two weeks since President Biden abandoned his reelection bid and endorsed her.

Some labor groups have criticized Kelly for opposing proposed legislation they argue would boost union organizing. Shawn Fain, president of the United Auto Workers, said that despite backing Harris for president, his 370,000-member union is not supporting Kelly as a potential running mate.

Fain also said the union does not favor Shapiro, who has previously proved willing to join with Republicans in calls to expand voucher programs that allow public tax dollars to flow to private schools.

Fain did single out Beshear, Walz and Pritzker for praise.

“She’s probably got a thousand people telling her the same thing, you know, of what they think,” Fain said in an interview. “And so she’s got to make the decision based off of what she feels is, you know, is best for her.”

The nonprofit Institute for Middle East Understanding said in a statement that Shapiro “is not the right candidate for the job, and selecting him would be a step in the wrong direction.”

Shapiro, who says he plans to be at Harris’ rally Tuesday in Philadelphia, has aggressively confronted what he views as antisemitism cropping up from pro-Palestinian demonstrations and he has professed solidarity with Israel in its drive to eliminate Hamas as it Israel battles the militants in Gaza.

Shapiro called out universities for not acting quickly to tackle antisemitism and he became a prominent critic of the University of Pennsylvania’s president, Liz Magill. She resigned after testifying at a congressional hearing where she was unable to say under repeated questioning that calls on campus for the genocide of Jews would violate the school’s conduct policy.

Shapiro has also criticized Israeli Prime Minister Benjamin Netanyahu, while suggesting that any end to the Israel-Hamas war requires the removal of Hamas from power.

The governor has been criticized by the Council on American-Islamic Relations for not condemning Israel for the killing of civilians in Gaza or for not calling for Israel to stop the fighting in the territory. Nearly 40,000 Palestinians have been killed in Israeli attacks in Gaza, according to the health authority there. Shapiro has countered that he has met with Muslim Americans and understands their pain.

The progressive activist organization RootsAction.org opposes Shapiro’s views on Israel, school vouchers and the environment, among other issues. It says that in considering Shapiro, Harris “has set off alarm bells among young people, racial justice organizers, Arab Americans, Muslims and others whose votes and campaign activism were crucial to defeating Trump four years ago.”

Meanwhile, the Philadelphia Inquirer resurfaced an opinion article Shapiro wrote in 1993 as a 20-year-old college student at the University of Rochester where he said peace “will never come” to the Middle East and that Palestinians were “too battle-minded” to coexist with Israel.

Asked about it, Shapiro responded, “I was 20,” adding that he long has supported a two-state solution to the Palestinian-Israeli conflict.

“It is my hope that we can see a day where peace will reign in the Middle East,” he said.

Also opposing Shapiro are some environmental leaders and residents of the rural town of Dimock, Pa. They have drafted a letter to Harris urging her not to choose Shapiro and alleging that the governor failed to keep his promises to clean up area groundwater contaminated by natural gas production via hydraulic fracturing.

Weissert writes for the Associated Press. AP writers Marc Levy in Harrisburg, Pa., and Tom Krisher in Detroit contributed to this report.