While most of us were sleeping, the Senate laid the groundwork for repealing the Affordable Care Act—and effectively strip 20 million Americans of their health care—by approving a budget resolution that will allow Republicans to gut key parts of President Obama's signature legislation.

The Affordable Care Act has not been repealed yet, but the Senate's vote is the first step in doing so. After a "vote-a-rama" that began around 6:30 p.m. on Wednesday and concluded shortly before 1:30 a.m. on Thursday, the Senate narrowly voted (51 to 48) in favor of a budget resolution that will allow major parts of the ACA to be repealed through a process known as reconciliation.

A reconciliation bill can be passed by a simple majority and without threat of filibuster. Republicans currently hold 52 of the Senate's 100 seats—last night, they almost-unanimously voted in favor of reconciliation. Rand Paul was the only Republican to vote against the measure, along with the Senate's 46 Democrats and two Independents.

As NPR notes, reconciliation only allows Congress to repeal the parts of the ACA that are related to government spending or taxation, like making health insurance compulsory and subsidizing Medicaid funds.

Reconciliation won't allow Congress to repeal other popular measures, like requiring companies to provide insurance for people with pre-existing conditions and allowing young adults to stay on their parents' plans, but Democrats worry that these provisions will be repealed as well. Last night, Democrats used their ability to propose unlimited amendments to essentially force Republicans to publicly oppose the parts of the ACA that are popular even among those who oppose "Obamacare."

The Washington Post reports that Republicans blocked six amendments proposed by Democrats within the first few hours of voting, including an attempt to prevent changes to Medicare and Medicaid. Other amendments intended to ensure that the most popular provisions of the ACA remain in place, like one guaranteeing coverage to people with pre-existing conditions, were similarly blocked by Republicans. Democratic leadership aides told the Post that they could use Republicans' votes during upcoming election midterm campaigns.

The Senate also struck down an amendment proposed by Bernie Sanders that would allow for the importation of cheaper prescription drugs from Canada and other countries—both Ted Cruz and Rand Paul voted in favor of this amendment, but 13 Democrats, including Cory Booker, voted against it.

Roll call was the Democrats' final opportunity to voice their opposition to reconciliation. Although senators aren't supposed to give speeches during a vote, each Democrat spoke out in support of the ACA during their vote, while Colorado Republican Cory Gardner, who was presiding over the vote, repeatedly called for order.

Below, video of Illinois Senator Tammy Duckworth (out of frame) loudly declaring, "For the 1.2 million Illinoisans who will lose health insurance with this repeal of the ACA, and for all those with pre-existing conditions, I stand on prosthetic legs to vote 'no.'"

According to the Times, the House could vote on reconciliation as early as Friday—Republicans' sudden efficiency shows that they think they'll be able to repeal key provisions of the ACA even before Donald Trump is inaugurated.

"This is our opportunity to keep our campaign promise," Mississippi Senator Roger Wicker told the Times. "This is our opportunity to help the president-elect and vice president-elect keep their campaign promises and show to the American people that elections have consequences."

But some House Republicans are concerned about starting the repeal process before having a replacement plan in place, the Post reports.

"We just want more specifics," Mark Meadows, chairman of the House Freedom Caucus, said. "I'm willing to take a vote today if we have the specifics. So it's not a much a slow it down for slowing-it-down purposes as it is, we need to know what we're going to replace it with."

You can ask your representatives to support the Affordable Care Act by calling 1-866-426-2631 and entering your zip code.