Sen. Susan Collins (R-Maine) is up against a steep challenge for her seat for the first time since 1996, according to a Colby College poll, which shows her in a statistical tie with her expected Democratic opponent.

Why it matters: As one of the most centrist Republicans in the Senate during Trump's presidency, Collins has served as a pivotal swing vote on a number of key issues.

She voted to confirm controversial U.S. Supreme Court nominee Brett Kavanaugh in 2018, and more recently she voted to acquit Trump in the impeachment trial.

Details: 43% of those polled indicated they would vote for Maine's House Speaker Sara Gideon in the November election, compared to the 42% who supported Collins.

49% of respondents in the poll agreed with Collins' decision to acquit Trump, compared to 50% who did not. 39% of independents polled said the decision made them less likely to vote for Collins; 13% said it made them more likely to do so.

The state of play: Collins is among a handful of Republicans who Democrats are hoping to unseat in a bid to reclaim the Senate majority, per WSJ. Democrats would need to pick up four seats in 2020 to achieve a majority.

Methodology: The poll surveyed 1,008 registered Maine voters Feb. 10–13. The margin of error is ±3%.