Eight senators broke from the Democratic caucus and agreed to a deal giving Republicans the 60 votes they needed to end the government shutdown. The measure still needs to be voted on in both chambers of Congress.

The Senate on Sunday night took the first step toward ending the longest shutdown in U.S. history, after a group of Democrats broke their party’s blockade and voted with Republicans to advance legislation to reopen the government.

The 60-to-40 vote paved the way for the spending agreement to begin making its way through Congress, where it would still need to be debated and passed by the Senate, win approval in the House and be signed by President Trump to bring the shutdown to a close.

Eight senators in the Democratic caucus voted to advance the measure, which would fund most federal agencies through January. That indicated there were enough votes to end weeks of gridlock that has shuttered the government for 40 days, leaving hundreds of thousands of federal workers furloughed, millions of Americans at risk of losing food assistance and millions more facing air travel disruptions.

But the deal prompted a quick and fierce backlash among Democrats, many of whom were livid that their colleagues had backed down from the party’s central demand in the shutdown fight: the extension of health insurance subsidies that are slated to expire at the end of the year, sending premiums soaring for millions of Americans.

The compromise measure included a provision that