Republican senators are confronting an unsettling possibility: Sen. Ted Cruz, their least favorite colleague, stands within reach of becoming the party's presidential nominee and standard-bearer.
Worse than that in their eyes, many GOP lawmakers and aides fear the Texas senator could ruin Republicans' chances of hanging onto control of the Senate in November's elections. They're concerned that he'll alienate voters in a half-dozen key swing states with his hardline stances on issues from immigration to abortion.
And yet, these Republicans say they're essentially powerless to stop Cruz. Any attempt to weaken him in his primary fight with Donald Trump only risks bolstering his argument that he's running against the "Washington cartel."