Most Republican elected officials take pains to stress that they don't support unauthorized immigration to the US but are in favor of maintaining or even expanding legal immigration, especially for high-skilled workers. But it looks like there might be a debate among the party's 2016 presidential contenders over whether legal immigration is really a good thing for the nation after all.

Wisconsin Gov. Scott Walker, who's trying to set himself up as the conservative alternative to Jeb Bush — and who's recently won praise from GOP uberdonor David Koch — has started stressing that legal immigration needs to be "based, first and foremost, on protecting American workers and American wages."

No politician is going to say that he or she doesn't care about American workers. But in the immigration debate, "protecting American workers" often means the politician believes legal immigrants compete with Americans for jobs, and that legal immigration should therefore be limited to make sure Americans stay employed.

And in case there's any doubt that Walker's endorsing that viewpoint, in an interview with Glenn Beck on Monday Walker name-checked Senator Jeff Sessions (R-AL) — the current chair of the Senate Immigration Subcommittee and the biggest opponent of legal immigration in Congress.

Sessions has said that his mission on the subcommittee is to "give voice to those whose voice has been shut out" in the immigration debate, including "the voice of the working families whose wages have been reduced by years of record immigration; the voice of the American IT workers who are being replaced with guest workers." He's already held a hearing on the H-1B visa for high-skilled guest workers, alleging that H-1B visa holders take American jobs and drive down American wages.

Walker was probably playing to Beck and his audience at least a little on Monday by making a point of saying, "I've talked to Sessions and others out there." But he used Sessions-esque language about a legal immigration system that "ultimately has to protect American workers" in an interview with Sean Hannity earlier in April.

After a flap last month in which Walker was accused of flip-flopping on "amnesty," it makes sense that he'd be trying to shore up conservative bona fides on unauthorized migration. But by emphasizing concerns about legal immigration, he's going further.

It's not unheard of for a Republican presidential candidate to oppose expanding legal immigration; Rick Santorum put out ads in South Carolina in 2012 on the issue. But it's certainly a minority position. While Mitt Romney was calling for "self-deportation" of unauthorized immigrants in the 2012 primary, he was also calling to "staple a green card to the diploma" of immigrants who graduated from US schools with STEM degrees as a way of increasing skilled immigration. And in the 2016 field, Sen. Ted Cruz (R-TX), the candidate who's perhaps been most vocal in opposing "amnesty," doesn't just support legal immigration — he's proposed drastically increasing the number of work visas the US gives out.

It's unclear whether Walker's populist immigration stance will lead to a real debate within the GOP primary about whether legal immigration is good for America. But after several years of the Republican position being "for legal immigrants, against illegal ones," it would be very interesting to see the first half of that stance called into question.