Sen. Susan Collins responded late Wednesday to a letter from the leaders of Maine’s Republican Party condemning her vote to impeach former President Trump for inciting the deadly Jan. 6 riot at the nation’s Capitol that left five people dead, including one police officer.

“My long history with the Republican party notwithstanding, as an impeachment juror, I swore to do impartial justice,” Collins said in a statement. “This is an oath I took very seriously, just as I did when I voted to acquit President Trump in the 2020 impeachment trial. The decisions I made in both trials were based on the Constitution and the evidence before me, not on my membership in a political party or any other external factor.”

Instead of taking issue with party leaders, Collins urged Maine Republicans to work on improving electoral results. She noted that Democrats won the presidential race in Maine and the state’s two congressional races while maintaining control of the state Senate and the state House.

“I hope that we are able to work together to improve our electoral results. Now would be a good time for us to consider how we can improve our performance in the 2022 and 2024 cycles,” Collins said.

Collins, the sole Republican senator from New England, won her fifth term in November after defeating Democratic challenger Sara Gideon.

In the letter to Collins on Wednesday posted on the Maine Republican Party’s Facebook page, Party Chairwoman Demi Kouzounas and members of the Maine Republican State Committee thanked Collins for the work she has done to support Republicans, but said they had “to condemn in the strongest possible terms your vote on Saturday, Feb. 13, to impeach President Donald J. Trump.”

Maine Republicans said the trial was unconstitutional because he was not the sitting president and that the proceedings were politically motivated by Democrats, who refused to accept Trump’s victory in 2016.

“We cannot, and will not, be silent in the wake of this vote,” they said.

Republicans also questioned the integrity of the impeachment presentation made by House managers.

“Some of us have registered serious concerns with the way the House managers altered video of President Trump to cast his speech in the worst possible light, ignoring his calls for peace, similar to the way a campaign might cut a dishonest 30-second campaign ad. The prosecution was certainly beneath the dignity of the Senate and the solemn nature of impeachment,” the Republican letter states.

Collins was one of seven Republican senators who voted to impeach Trump. The North Carolina Republican Party voted to condemn Sen. Richard Burr for voting to convict and the Louisiana Republican Party voted to censure Republican Sen. Bill Cassidy.

Sens. Lisa Murkowksi of Alaska, Mitt Romney of Utah, Ben Sasse of Nebraska and Pat Toomey of Pennsylvania also voted to impeach Trump, who was acquitted by a vote of 57-43, short of the two-thirds majority needed.