The Senate on Monday will take its first vote on the Women’s Health Protection Act, a bill aimed at codifying the right to an abortion.

Democrats hope to use the vote to show support for abortion rights as they come under attack in numerous states, and as they face a challenge in the Supreme Court. The vote, however, is widely expected to fail: Republicans are broadly opposed to the legislation and will likely filibuster it. Once filibustered, the bill would need 60 votes to advance, support it doesn’t currently have in a 50-50 Senate.

Democrats don’t appear to be fully united on the vote, either: Only 48 of the 50 lawmakers in the Senate Democratic caucus have signed on to co-sponsor this bill. Sens. Joe Manchin (D-WV) and Bob Casey (D-PA) have not sponsored the legislation, though Casey has said he’ll back Monday’s vote, which is to open debate on the bill. Manchin has yet to indicate whether he’d support the bill or Monday’s procedural vote.

On the Republican side, Sens. Susan Collins (R-ME) and Lisa Murkowski (R-AK) have both backed abortion rights in the past, though Collins has previously said she thinks the Women’s Health Protection Act is too expansive, and Murkowski hasn’t said where she stands.

Although it’s a doomed bill, the consideration of the Women’s Health Protection Act is still important. By holding a vote on the legislation, Democrats are highlighting abortion rights as a priority and getting lawmakers — including vulnerable Republicans — on the record about where they stand.

Because the vote isn’t expected to pass, its purpose is primarily to send a political message and to demonstrate to voters that Democrats are listening to them, and trying to advance this issue. By taking it, Democrats hope to energize their base and draw a stark contrast with GOP leaders in the upcoming elections. Given most Americans, including 35 percent of Republicans, support abortion rights, activists believe this vote can help make their case in competitive midterm races.

“It’s really important to take these critical votes on issues that matter to the American people so voters understand where their elected officials are,” said Kristin Ford, a vice president of communications and research for NARAL, a group that advocates for abortion rights.

What the Women’s Health Protection Act would do

The Women’s Health Protection Act would enshrine into federal law the right to access and perform an abortion, and it would supersede state laws on the issue. That’s notable because it would effectively neutralize laws in 19 states that have sought to severely curb access to abortion or ban it altogether.

Such restrictions have disproportionately harmed low-income women who are already less likely to have health care coverage for abortions, and who face more obstacles accessing alternative options if their states put in barriers. According to an ABC News report, Black and Hispanic women in conservative states will also bear the outsize impact of abortion restrictions in these places because they’ve had higher abortion rates.

If passed, the Women’s Health Protection Act would bar six-week and 20-week bans on abortions. It would also prohibit policies, like ultrasound requirements and waiting periods, that attempt to make it more burdensome to obtain an abortion. The text of the legislation makes it clear that it’s a direct response to what the bill’s sponsors say are more than 500 state and local laws limiting abortion access implemented in some way since 2011.

Democrats’ consideration of the bill comes as Republican-led states have ramped up efforts to ban abortions, including a six-week ban Texas instituted last year, and as the Supreme Court weighs a case that could severely dilute the protections offered by Roe v. Wade.

The proposed federal law would provide sweeping protections that ensure that people have abortion access even if the Supreme Court rules to weaken reproductive rights. It wouldn’t, however, supersede laws addressing insurance coverage for abortions. Previously, there have been strict limits on Medicaid coverage of abortions because of the Hyde Amendment’s restrictions on the use of federal funding for such health care.

“People are counting on the Senate to do what the Supreme Court will not,” Nancy Northrup, the president of the Center for Reproductive Rights, said in a statement. “The hardship and chaos in Texas right now is coming to other states soon, unless the right to abortion is protected through federal legislation.”

The vote also makes the case for a larger Democratic majority

In addition to revealing where lawmakers stand, the vote also makes the case for a larger Democratic majority.

Because Democrats have such narrow margins in the Senate, they aren’t able to advance most bills if they get blocked by Republicans. Additionally, their razor-thin 50-50 majority means that any Democratic defections would still stymie the legislation even if the filibuster were to be eliminated.

If Democrats were able to keep all of the Senate seats they currently hold, and win the seats currently held by the GOP that the Cook Political Report rates as “toss-up” or “lean Republican,” they’d gain five seats. That’s an unlikely prospect, but they’ll try to argue for it this fall with votes like the one on the Women’s Health Protection Act.

In certain battleground states including Pennsylvania and Wisconsin, a narrow majority of adults have said they believe abortion should be legal in all or most cases, according to a 2014 Pew survey. Support for abortion rights was slightly less robust in other purple states like Georgia and Arizona. Advocates hope this vote will be compelling for swing voters in places where abortion rights have strong support, and a motivating force for the Democratic base.

Even if they were to pick up more seats, Democrats would still need Republican support to hit a 60-vote threshold to overcome filibusters. But they’d potentially have the 51 votes needed to eliminate the filibuster or to establish a carve-out for certain bills, including legislation to protect abortion rights.

That’s a tantalizing possibility for Democrats, who have spent two years seeing their legislative goals blocked by the Republican minority. Ford notes that Monday’s vote could play an important role in reminding voters of the importance of winning every race possible ahead of the midterm elections.

“We need to secure more seats so we can advance legislation like this that is so critical, and so aligned with mainstream public opinions,” Ford said.