AUSTIN, Texas (AP) — Ted Cruz once proudly wore a belt buckle borrowed from George H.W. Bush that said: "President of the United States."

He campaigned and worked for that former president's son, George W. Bush, also a White House occupant. And the endorsement of George P. Bush, the family's latest rising political star, lent credibility to Cruz's then little-known 2012 Senate campaign.

Now, though, things aren't so simpatico between the Bushes and Cruz — and not only because one of the Texas senator's GOP presidential primary competitors is the father of George P. Bush, former Florida Gov. Jeb Bush.

Rising tensions reflect Cruz potentially helping to dent the Bushes position as one of the nation's pre-eminent political families. And they underscore a deeper internal GOP struggle between insurgent conservative outsiders and the establishment.

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