Sen. Susan Collins (Maine) became the only GOP senator to break with her party during a marathon session over the rules for the Senate’s impeachment trial of President Trump.

Democrats forced a 10th amendment vote early Wednesday morning that would extend the amount of time House impeachment managers and Trump’s legal team have to respond to motions.

Currently, both sides can file motions around 9 a.m., including a potential motion to dismiss the charges against Trump. Under the rules, the opposing side would have to respond by 11 a.m. The amendment by Democrats would extend that time, giving them until Thursday to respond.

A spokeswoman for Collins didn’t immediately respond to a request for comment about why she broke with her party and voted against tabling the amendment.