In the summer of 2019, as a crowded Democratic primary was picking up speed, Joe Biden was on the defensive, pummeled by abortion-rights groups and his opponents for his support of the Hyde Amendment, a measure that prohibits the use of federal funds for most abortions.

He reversed his position, but the episode underlined his wobbly standing in the eyes of abortion-rights activists as he faced off in 2020 against Donald Trump, who became a hero of the anti-abortion movement by using his presidency to appoint Supreme Court justices who appeared likely to overturn Roe v. Wade.

Now, in 2024, the tables have turned.

This week, it was Trump angering abortion opponents as he sought to wash his hands of the matter and leave it to the states, while President Biden depicted himself as a direct champion of the cause, releasing a stark TV ad and excoriating Trump as he sought to position the issue at the center of his re-election campaign.

“I am determined,” Biden said, “to restore the federal protections of Roe v. Wade.”

If you were going to invent two candidates for the first presidential election since the fall of Roe, neither side of the abortion divide would probably design the exact candidate they have. They are both white men. They are both old. And neither has always said what their respective side of the debate wants to hear, although Biden’s shift on the Hyde Amendment is not as stark a reversal as Trump’s flip over the years from “pro-choice” to “pro-life.”

So the week’s events, with the Arizona Supreme Court ruling on Tuesday upholding an 1864 law banning almost all abortions, offered a window into an uncanny moment that for both has been a long time coming.

It is now Biden, a Catholic who has openly expressed personal misgivings about the issue, making abortion more central to a presidential campaign than any major-party nominee in history, while Trump, a former president who is usually happy to take credit for rolling back abortion rights, is trying to skirt it.

And neither will be able to control where the issue, which will turn on court rulings, referendums and decisions by state legislatures, goes from here.

“The people who are driving the agenda and the headlines are not necessarily people in Biden world or Trump world,” said Mary Ziegler, a law professor at the University of California, Davis, who studies the history and politics of abortion. “They’re kind of prisoners of the moment.”

A flip on Roe, and a retreat from a national ban

The week began with a bout of wishful thinking from Trump. After appointing three of the Supreme Court justices who overturned Roe, sending the contentious debate over abortion back to the states and igniting a firestorm of abortion-related political fights all over the country, he sought to turn down the heat on the issue by, well, leaving the issue up to the states.

The Arizona ruling immediately revealed the political perils of that strategy. Republicans around the state, including the Senate candidate Kari Lake and at least two congressmen seeking re-election, slammed the ruling. The Biden campaign swiftly moved to depict Trump as responsible for removing the national abortion protections in Roe that had prevented old laws like that from taking effect.

“That will be straightened out,” Trump told reporters Wednesday as he arrived in Georgia before a fund-raiser. “I’m sure that the governor and everybody else are going to bring it back into reason.” (The Trump campaign did not return a request for comment.)

Trump’s allies on the religious right, meanwhile, were deeply disappointed with what they see as a flip-flop. Their alliance with Trump had always been uneasy — Trump called himself “pro-choice” in the late 1990s, but by 2011 had reversed his position entirely, calling himself “pro-life.” He won over evangelical support during his 2016 presidential race by promising to appoint anti-abortion judges.

“Scripture advises us, in Psalm 146 actually, to not place our trust in princes or kings or candidates for that matter,” said F. Brent Leatherwood, the president of the Ethics & Religious Liberty Commission, which is the policy wing of the Southern Baptist Convention. “These are people that are unreliable and inconsistent.”

Personal misgivings, but a long defense of Roe

It used to be Biden who was accused of modulating his position on abortion over politics, frustrating activists on both sides of the issue.

“Joe Biden moans a lot and then usually votes against us,” a top Planned Parenthood official told The Wall Street Journal in 1986. In the same piece, an official with National Right to Life complained he had “made a political judgment that he should be more pro-abortion.”

For much of his career, Biden supported the Hyde Amendment but also took votes in support of Roe. Over the years, he has spoken repeatedly of his discomfort with the procedure, including at a fund-raiser in February.

“I’m a practicing Catholic,” Biden said, according to a transcript provided by the White House. “I don’t want abortion on demand, but I thought Roe v. Wade had it right.”

Comments like that, as well as his well-documented reluctance to use the word “abortion,” have frustrated advocates who work on the issue.

“Whatever internal thoughts and feelings he might have on it personally, he’s the president of the United States,” said Kellie Copeland, the executive director of Pro-Choice Ohio. “People are suffering because they can’t access abortion. He should say that directly and plainly.”

Lauren Hitt, a spokeswoman for the Biden campaign, said that the president had long fought to protect abortion rights, and disputed the comparison between Trump and Biden. “For more than 50 years, Joe Biden has fought to protect Roe and women’s right to choose. As a senator, he voted repeatedly to protect Roe, and as president, he has used his full executive authority to fight back on extreme MAGA abortion bans,” Hitt said.

Biden’s leftward shift on abortion rights might lag behind some in his party — but it reflects decades of engagement with the issue, according to my colleague Lisa Lerer, who with Elizabeth Dias is writing an upcoming book on the fall of Roe.

Biden, Lisa said, has probably thought more deeply about abortion than any president in the modern era.