A casual observer of the 2016 presidential election and immigration politics could be forgiven for thinking that Republicans have moved sharply to the right on the issue, while Democrats have stayed roughly where they have always been. But an interesting new Pew poll suggests the opposite is true: Republican voters’ views on immigration have held roughly steady over the past decade, while Democratic voters’ views have lurched sharply to the left:As the attached figure from Pew shows, in 2006, 34 percent of Republicans said that immigrants “strengthen the country”; today, 35 percent say the same. Democrats, on the other hand, underwent a massive (nearly 30-point) pro-immigration shift over the last 10 years. So while Trump’s rise probably reflects a stronger mobilization of anti-immigration voters than the GOP has seen before, it may not be the case that the average Republican voter is in such a different place on immigration than he was during the Bush years. Meanwhile, the Democrats’ lurch leftward on immigration—while not covered as extensively as Trump’s various immigration-related outrages—has been visible to anyone willing to look: at the Univision debate last month, for example, both Democratic presidential candidates essentially promised to suspend immigration enforcement altogether.The standard media narrative holds that political polarization in the United States a GOP-driven phenomenon; that Republicans have gone off the deep end, and that Democrats remain sensible, centrist, and open to compromise. As we’ve said before, however, the truth is much more complicated. As much as many bien pensants would like to lay blame for our angry and polarized politics at the feet of racist Republicans, the Democrats’ dramatic leftward pivot—on issues from the $15 minimum to immigration to the culture wars—has clearly played a major role.