I’m not sure Mike Johnson himself fully knows why he decided to bring the Ukraine bill to the floor. And I have no special insight. But I think it might be driven in part by…
What you see from here you don’t see from there - Ariel Sharon (shortly after becoming Prime Minister)
Mike Johnson went from back bencher to Speaker. He did not have the slow upward path in the leadership where, at each step, he learned more on the key questions, and could then slowly adjust his views based on additional information.
And to be honest, in the case of a lot of politicians, that slow path to learning more lets them sell their soul one tiny bit at a time. No single step seems like that big a deal.
In the case of Mike Johnson he suddenly was getting detailed intelligence estimates. Coming from the best analysts we have, who lay out in addition to what the true situation is, the likely consequences of action or inaction on the part of Congress.
I think getting that all at once had a giant impact.