I saw it recently in BC, Canada, when the provincial Liberal party got bought out lock stock and barrel. It almost made me applaud, even though I was explicitly among the targeted "to be screwed".
It can only happen if the bought out party is extremely weak.

Once bought out, I don't see any possible redemption. You can't buy it back.

What can you say when already back in Oct. 45 members of the Democratic progressive caucus rushed out the door to endorse Hillary Clinton, and only one had the guts to back Sanders? That's so weak that it's barely perceptible. Clearly rife with trojans and other weak characters.

Big money isn't chickenshit. When big money buys a politician and buys a few think tanks to provide the MSM 24/7/52 fodder, and buys the MSM which in turn buys a few fake "progressive" opinionators/bloviators to round out a pretense, they cover every bet, and they do it by both instinct and training. They don't spare a nickel in vetting and buying the best.