No one has been more aggressive in going after Bush than Paul. The day Bush announced he was pursuing a potential candidacy, the Kentucky senator began running digital ads on Google taking aim at him. After Bush came clean to using marijuana while at Phillips Academy, Paul suggested he was being phony, pointing out that he’d refused to support legalization of the drug. “Had he been caught at Andover, he’d have never been governor, he’d probably never have a chance to run for the presidency,” Paul said.

In late January, Paul pulled off an eyebrow-raising stunt, releasing a mock Bush-Clinton phone call tweaking them for being in political dynasties and imagining them trying to work out a 2016 pact.

Others eager to seize the conservative mantle are piling on. Appearing on ABC’s “This Week” on Sunday, Cruz suggested Bush’s record was insufficiently conservative.