If George H. W. was the tree of the Bush clan, then George W. was Shrub (h/t Molly Ivins). And Jeb Bush is Sprig. I cite as evidence his pronouncements about the Iran nuclear agreement. Brian Beutler of the New Republic has a good look at Sprig's view of the agreement, his penchant for war, and, most disturbing, the complete lack of any (public) dissent among his fellow Republican candidates for President.
... Bush has now rolled out, and adhered to, a tangle of views that could be mistaken for his brother’s—void the Iran agreement and possibly attack Iran, rescind President Barack Obama’s 2009 executive order banning torture, and possibly send thousands of U.S. troops back into Iraq—and none of them is even remotely controversial among his co-partisans.
This matrix is slightly oversimplified, but only slightly. Thanks to the agreement, there’s a decent chance that Iran won’t produce a nuclear weapon for many years. If the agreement collapses, the diplomatic channel will essentially be closed, Iran will probably manufacture a weapon, and the drumbeat for airstrikes will intensify. That’s a cardinal truth, no matter who violates the agreement. The ancillary benefit for hawkish Iran foes is that if Iran breaches the deal, it will provide U.S. policymakers with a robust rhetorical foundation for demanding the reimposition of sanctions, and coordinated airstrikes. Republicans are effectively saying that this isn't good enough, and that we should void the deal ourselves—sacrifice all of that good will—to precipitate the crisis more rapidly.
That’s what Jeb Bush meant, in his foreign policy address last week, when he said, "If the Congress does not reject this deal, then the damage must be undone by the next president—and it will be my intention to begin that process immediately." Ripping up the global powers agreement is the predicate for the "pretty good deal" Republicans have in mind. It’s the whole show.