WASHINGTON — Senate Majority Leader Chuck Schumer says Democrats’ abortion legislation is “very simple,” as it would enshrine into federal law the landmark 1973 Roe v. Wade decision that legalized abortion nationwide.

Senate Democrats are moving quickly to try to codify the 50-year-old ruling after a draft U.S. Supreme Court opinion suggesting the court is poised to overturn the case was leaked last week. But they don’t have enough votes, and Republicans are expected to block the bill in a test vote Wednesday.

But if the Democratic legislation were to become law, it would do more than just preserve the status quo.

The bill would also expand protections, invalidating many state laws that Democrats and abortion rights advocates say have infringed on the original 1973 ruling. Two Republican senators who support abortion rights have indicated they won’t vote for it, instead favoring their own, narrower legislation.

A look at the legislation the Senate is voting on Wednesday:

CODIFYING ROE V. WADE

Broadly, the main objective of the legislation is to codify Roe v. Wade into federal law, meaning it would be much harder for the Supreme Court to overturn. In the five decades the ruling has been court precedent, abortion-rights supporters have not been able to pass federal legislation to legalize abortion. And because the Supreme Court decided on that right, it can also take it away — however rare that move may be.

In codifying Roe, the legislation would establish that health care providers have rights to provide abortion services and that patients have a right to receive abortions.

BANNING CERTAIN RESTRICTIONS

The Democrats’ bill would also end certain state laws that they say have chipped away at the original Roe v. Wade decision, banning what they say are medically unnecessary restrictions that block access to safe and accessible abortions. The court has allowed states to regulate but not ban abortion before the point of viability, around 24 weeks, resulting in a variety of state laws and restrictions that abortion-rights supporters oppose.

The bill would end bans earlier than 24 weeks, in addition to any restrictions that do not make exceptions for the patient’s health or life. It would also stop states from requiring providers share “medically inaccurate” information, or from requiring additional tests or waiting periods, aimed at dissuading a patient from having an abortion.

REPUBLICAN ALTERNATIVE

Republican Sens. Susan Collins of Maine and Lisa Murkowski of Alaska support abortion rights but have opposed the Democratic legislation, saying it is too expansive and could threaten some religious liberties that states have sought to protect.

They have introduced legislation that would hew closer to what the court currently allows, more generally prohibiting states from imposing an “undue burden” on the ability of a woman to choose whether to have an abortion prior to fetal viability. It is not expected to get a vote.

NEXT STEPS

Without the votes to pass their bill, Democrats have few options to block the eventual court ruling, if it overturns Roe v. Wade.

Democratic leaders have signaled that they instead intend to take the fight to voters ahead of this year’s midterms.

“We’ve got to win elections,” Sen. Chris Murphy, D-Conn., said Tuesday.