They will just ignore it and campaign anyway.
They need 67 to convict, including 20 GOP votes. Them campaigning would be six votes short for an impeachment conviction. Remember, they need 2/3 of Senators PRESENT to convict. They would need 64 to convict, needing 23 GOP votes (2/3*(100-6)=64).
I think 20 GOP votes is attainable, but those last four might be a stretch.
Impeachment Could Keep Senators Running For President Off The Campaign Trail For Weeks
Daily Caller ^ | October 18,2019 | Mary Margaret Olohan
FR Posted by Jayster
An impeachment trial of President Donald Trump could keep Democratic presidential candidates who are also senators off the campaign trail for weeks.
New Jersey Sen. Cory Booker, Colorado Sen. Michael Bennet, California Sen. Kamala Harris, Minnesota Sen. Amy Klobuchar, Vermont Sen. Bernie Sanders, and Massachusetts Sen. Elizabeth Warren would be required to stay in Washington, D.C., during an impeachment trial, according to BuzzFeed News.
Senate rules require senators to be present in session Monday through Saturday beginning at noon every day for an impeachment trial, BuzzFeed reported. Former President Bill Clinton’s impeachment trial took several weeks.
Bennet said he is unsure whether he could continue campaigning if an impeachment trial takes place, he told BuzzFeed.
(Excerpt) Read more at dailycaller.com ...
This, they’ll just say “I’m voting guilty no matter what, there’s no point in hearing the evidence or being present at the trial.” And dem voters will applaud for this.
So long as rules are not written in the Constitution they will be ignored or changed as needed.