CNN  — 

On the eve of the most important day in the Senate impeachment trial, momentum appeared to be moving against the Democratic desire to call witnesses to testify before a final vote on President Donald Trump’s removal could be held.

Republican leaders, who were somewhat pessimistic earlier in the week about their ability to keep four of their own members from defecting on the witness vote, were sounding significantly more confident about their chances by Thursday.

One of the main reasons for that increased confidence was the fact that there appeared to be very little desire among the bulk of the endangered GOP senators up for reelection this fall to break with their party and the President on the vote.

In fact, with the exception of Maine Sen. Susan Collins, it looks likely that all of the targeted Republican senators will oppose both the call for witnesses and the ultimate removal of Trump.

Why? Colorado Sen. Cory Gardner, who sits in a state Hillary Clinton won in 2016 and is considered an underdog for an second term, explained the reasoning in his statement opposing witnesses:

“I do not believe we need to hear from an 18th witness,” Gardner said, adding that he had “reached this decision after carefully weighing the House managers and defense arguments and closely reviewing the evidence from the House, which included well over 100 hours of testimony from 17 witnesses.”

The message hiding in between the lines of Gardner’s statement is simple: Democrats won’t be satisfied with calling John Bolton as a witness. They’ll want more after Bolton. And the trial will drag on and on and on. And the closer it gets to the election, the more politically fraught it will be for every politician trying to make their race about much more than just Trump.

Under this logic, a vote against witnesses ends the trial tomorrow (or shortly thereafter). With hopes that by November’s election, the impeachment trial of late January is largely forgotten by voters.

The Point: Gardner and his colleagues in similar positions – Sens. Martha McSally of Arizona, Thom Tillis of North Carolina, Joni Ernst of Iowa, etc. – believe (or have been convinced) that a short impeachment trial ending with total support for Trump is their best chance to get reelected.