WASHINGTON — The Senate rejected a bill on Monday to ban most abortions after 20 weeks of pregnancy, a largely symbolic vote aimed at forcing vulnerable Democrats to take a stand that could hurt their prospects for re-election in states won by President Trump.
By a vote of 51 to 46, the measure fell well short of the 60-vote threshold required for the Senate to break a Democratic filibuster. The outcome was not a surprise, and the vote fell mostly along party lines.
The Senate voted on a similar measure in 2015. At that time three Democrats — Senators Bob Casey of Pennsylvania, Joe Donnelly of Indiana and Joe Manchin of West Virginia — voted in favor of it. All three are up for re-election this year in states that Mr. Trump carried, and all of them voted in favor of the measure again on Monday. Two Republicans — Senators Susan Collins of Maine and Lisa Murkowski of Alaska — voted against it.
The bill, which has the strong backing of the Trump administration, is identical to one that passed the House in October and similar to legislation that has been adopted in 20 states. It would make nearly all abortions after 20 weeks illegal; anyone who performed the procedure could face a potential prison term of five years, fines or both, though exceptions could be made when the life of the mother was at risk, or in cases of rape or incest.
“To those who believe in this issue, we will be back for another day,” Senator Lindsey Graham, Republican of South Carolina and the chief sponsor of the bill, said in advance of the vote. To his colleagues who supported the measure, he said: “You’re on the right side of history. You’re where America will be. It’s just a matter of time before we get there.”
The Senate floor debate offered supporters and opponents of abortion rights an opportunity to speak expansively about Roe v. Wade, the landmark 1973 Supreme Court decision legalizing abortion — and they took it.
“Forty-five years after Roe v. Wade, abortions are safer today than getting your tonsils out,” declared Senator Elizabeth Warren, Democrat of Massachusetts. “A lot of women are alive today because of Roe.” She called the ban “part of a broad and sustained assault by Republican politicians on women’s rights to make decisions about their own bodies.”
But Senator Thom Tillis, Republican of North Carolina, said it was time for the Senate to act.
“The life of the unborn is a precious life, and we as members of the United States Senate and the U.S. Congress are tasked with making sure we protect all lives in America,” Mr. Tillis said, adding, “This is just a very important, precious, helpless part of the population.”
The 20-week ban, named the Pain-Capable Unborn Child Protection Act, is central to the strategy of the anti-abortion movement, which is newly emboldened under Mr. Trump. The president’s election in 2016 ushered in a wave of anti-abortion victories in states like Ohio, where lawmakers adopted a 20-week abortion ban in December of that year.
Abortion foes say that if enough states pass such bans, Congress will be more likely to follow. They note that it took their movement 15 years to persuade Congress to outlaw the procedure that opponents call partial-birth abortion. They see the 20-week abortion ban on a similar trajectory.
“We are building momentum for eventual federal legislation,” said Mallory Quigley, a spokeswoman for Susan B. Anthony List, a group that works to elect anti-abortion candidates. She added, “We want to get vulnerable Democrats who are up for re-election this year on the record once again.”
Abortion rights advocates, meanwhile, say the opponents are badly misreading the political climate. In the era of the #MeToo movement, they say, Republicans will face a backlash for supporting a bill that prevents women from taking control of their own health care decisions.
“I think they fail to recognize the context of the moment and what they’re contending with,” said Ilyse Hogue, the president of NARAL Pro-Choice America, an abortion rights advocacy group. “We are seeing a rising up of women, unprecedented in my lifetime, and women who recognize that the role of abortion rights is so crucially important for women’s health.”
Jennifer Duffy, who tracks Senate races for the nonpartisan Cook Political Report, said vulnerable Republicans — she cited Dean Heller in Nevada — might have as much to lose in voting for the measure as vulnerable Democrats had in voting against it.
“Since when’s the last time we saw a Democrat pay for what is essentially a pro-choice vote?” Ms. Duffy asked. “It’s been a long time.”
Polling by the Pew Research Center shows that backing for abortion is as high as it has been in two decade. As of 2017, 57 percent of Americans said abortion should be legal in all or most cases, while 40 percent said it should be illegal in all or most cases. But the issue animates social conservatives; 71 percent of conservative Republicans said abortion should be illegal in all or most cases, the Pew poll found.
The United States is one of just seven countries — including China and North Korea — that permit elective abortion after 20 weeks, a fact that backers of the failed measure brought up repeatedly on Monday.
“The United States keeps the company of countries like China and North Korea. They deny unborn children the most basic of protections,’’ Senator Joni Ernst, Republican of Iowa, said on the Senate floor Monday. “This, folks, is not who we are as a nation.”
Supporters of the ban cite medical studies suggesting that fetuses can feel pain at 20 weeks. But the science surrounding fetal pain is complex. In a July 2013 memo, the American Congress of Obstetricians and Gynecologists wrote that “the fetus does not even have the physiological capacity to perceive pain until at least 24 weeks of gestation.”