I'll be fair here.
I will give him credit for doing one thing right.
Back in '98 in GR when he was running for AG against Smietanka, the kakistocracy pulled out all of the stops that day to make things go their way.
Denying credentials to delegates. Calling for re-votes. Multiple challenges to the processes in motion.
Sound familiar?
In the end, the blue-bloods failed miserably and were becoming visibly worried on the dais. Those in attendance were well on their way towards an all-out open revolt at the blatantly obvious shenanigans being pulled that day.
Seeing what was happening, Romney showed a little backbone (far more than those running the convention IMHO) and announced his withdrawal from the race.
Does that one act alone make him US Senate material?
No.