South Carolina senator Lindsay Graham, a virtual spokesman for the Republican establishment, once contended that choosing between Ted Cruz and Donald Trump was akin to deciding whether to be poisoned or shot.

Judging by his recent endorsement of Cruz, Sen. Graham prefers arsenic. Jeb Bush, another establishment candidate crushed by the Trump bulldozer, also just reluctantly endorsed Cruz, explaining that the Texas senator is the only one who can possibly "overcome" Trump.

As Trump marches towards his seemingly inevitable nomination, the biggest question isn't how the GOP power-brokers can stop him. It's why they would want to.