In the United States there have long-standing disagreements concerning what to do about illegal immigration. But it seems to me that prior to the 2016 election, the mainstream of both U.S. political parties favored increased legal immigration, to the point where Scott Walker's vague suggestion that he might be in favor of reducing legal immigration actually hurt him in the early days of the 2016 Republican primary campaign. Yet by the end of the 2016 campaign, and afterwards, it's become fairly common on the Right to favor reduced legal immigration.
So my question is, did Donald Trump shift the immigration debate to the right? Has there been any political science research on this?
One counterpoint to Trump being the cause is the concomitant rise of nationalist parties in Europe opposing legal immigration, but I could foresee a situation where in the absence of Trump, U.S. political thought diverged from that of Europe.