Bribery? What's wrong with that?

I would not doubt that is exactly what happened. The rep was fearful that voting for impeachment would negatively affect his re-election. Put with that the assumption numerous Democrats were approached about trading their votes for campaign cash. No way to trace money from "Trump" to a candidate. Even if he did hand the money to the candidate by way of a check. Trump won't release his finances. The "donation" should be seen in the candidate's disclosure paperwork. Trump knows that. So, the donation would either be in cash... untraceable... or a proxy would have made the donation. Any one of a few thousand Trump cultists would have gladly been a "carrier" of money from Trump's hand to the rep's hand. Disclosure paperwork would show the money from the proxy, not Trump.

Trump has bought off attorneys, plaintiffs, politicians for decades. Why would anyone believe this corrupt personality would suddenly change when elected to the White House??