The reverberations from Sen. Kyrsten Sinema’s (Ariz.) announcement on Friday that she has left the Democratic Party and is now an Independent are being felt across the political spectrum, but especially in the Senate itself where lawmakers are evaluating how her decision will change the dynamics of the chamber.

Sen. Raphael Warnock’s (D-Ga.) runoff victory on Tuesday gave Democrats an anticipated 51-49 majority in the upper chamber, with the one extra vote handing them a significant advantage over the current 50-50 split that ranges from subpoena power to the ability to move nominees through committees more swiftly. 

That bit of breathing room lasted a grand total of two days, with Sinema’s official independence creating potential issues for Democratic leadership and Senate Majority Leader Charles Schumer (D-N.Y.) in their quest to keep the conference united and continue to move President Biden’s agenda. 

“This is the start of a two-year-long headache for Sen. Schumer,” said Jim Manley, a former top aide to Senate Majority Leader Harry Reid (D-Nev.) and Sen. Ted Kennedy (D-Mass.) “I don’t envy what he is going to have to do to keep on board with the Democratic agenda, but as long as he keeps open the line of communication, it could work.”