On Senate floor, RoJo's stance was, nothing to see. Like the incumbency he hid.

So Wisconsin's senior 'US Senator' 

helped block that body's acceptance of witnesses and evidence which documented the behavior for which Trump was impeached and about which Johnson had direct knowledge:

Despite Involvement, Sen. Ron Johnson Will Not Recuse Himself From Impeachment Trial

That's about what you'd expect from a politician who ran for re-election to the Senate in 2016 by pretending he was still an outsider, not an incumbent

Roll Call reported:

Republican Ron Johnson is a first-term U.S. senator from Wisconsin. The voters back home wouldn’t know it watching his re-election campaign’s first TV ad...It doesn’t once mention his work as a lawmaker or even identify him as a senator...

The Republican’s re-election ad is carefully designed to give viewers the impression that he’s not already a senator. 

In the spot, Johnson makes literally no references to any work he’s done while in office; he doesn’t identify himself as a senator; he doesn’t note any Senate achievements; and he doesn’t mention that he’s running for re-election.

Instead, the far-right Wisconsin lawmaker and committee chairman boasts in the ad, in the present tense, “I manufacture plastic,...” 

He goes on to say, “I’ve stayed put, right here in Oshkosh, for 37 years.” Left unmentioned: the last six years in which he’s been a powerful Beltway insider.

Represent the people? Respect an oath of office?

Contempt for both apparently feels better.