Given Rubio’s background and voting record in the U.S. Senate, some Republicans are having trouble with Cruz’s description of him as a “moderate.”

“Of course he isn’t,” said Katie Packer Gage, deputy campaign manager for Mitt Romney in 2012. “Cruz is being purposely misleading. It’s dishonest.”…

Rubio has scored a rating of 90 percent from Heritage Action, 93 percent from the Club For Growth, and 98 percent from the American Conservative Union, three conservative groups that grade Republicans on purity. By contrast, Cruz’s ratings are 98 percent, 96 percent, and 100 percent—not a huge difference. Both are far above the GOP average and rank among the most ideologically conservative senators.

“If we separate ourselves from the current universe that is the Republican Party, Rubio is at the right end of the spectrum,” said Norm Ornstein, a congressional scholar at the American Enterprise Institute.