From where I stand, John Kasich has been had. He sold out the troops after the '94 revolt brought fresh blood to Congress thinking he could make change from within. The stench got bad enough for him to quit.
He's been branded, and now he's only one of the herd.
He won't be back to testify about anything.
Actually, the same could be asked about all of Gory Conduit's cronies in DC -- the main point is: how thoroughly have the DC cops investigated ALL those that may have relevant input (Kasich being prime candidate) -- my guess is that they haven't bothered any of the 'power elite.'