Elaina Plott writes for National Review Online about opposition within the U.S. House Republican caucus to naming Wisconsin congressman and former vice presidential candidate Paul Ryan as the next U.S. House speaker.

The man who was once the party’s fresh-faced vice-presidential nominee, lauded for his aggressive calls to overhaul Medicare and Medicaid and portrayed by Democrats as the arch-conservative villain who would toss Granny off a cliff, now finds himself the latest target of some of conservative media’s biggest stars.

That’s mostly a result of Ryan’s support for comprehensive immigration reform, perhaps the one position most guaranteed to breed distrust and ill will among much of today’s conservative base. With such animosity suddenly bubbling to the surface, some of the same people who rallied around Ryan during the 2012 presidential race are now working to thwart his bid for House speaker before it’s even begun. It’s a testament both to the outsize role the issue of immigration has taken on within the Republican party and to the ever-widening chasm between the grassroots and establishment. …

… To be sure, there are other reasons for conservative discontent: Ryan’s support for Trade-Promotion Authority and the Trans-Pacific Partnership, which the far Right has painted as an executive power grab; his collaboration with Democratic senator Patty Murray on a federal budget compromise; and his reported unwillingness to grant the House Freedom Caucus the procedural concessions it is demanding.

But it was Ryan’s defection on immigration, it seems, that first signaled to some conservatives that he may not be one of them. Ryan holds a D-minus rating with NumbersUSA, a non-partisan organization that seeks to reduce immigration back to what it calls “traditional levels.” Ryan is “unacceptable,” says the organization’s president, Roy Beck. “He combines a sentimentalist view of immigration that’s not practical, and he represents the immigration policies of crony capitalists. To put somebody as speaker who is so tied to this image is detrimental to the GOP. They need to try to be a party that wage-earning Americans believe in.”