The third leap is the idea that immigration is a wedge issue that only divides Republicans – by pitting moderates like Bush and business interests against the right’s populists. The reality is that the Democratic coalition is almost as easily divided by the issue: Many working-class Democrats, white and African-American alike, are skeptical of immigration for the same reason that they’re skeptical of free trade agreements — because both tend to expose them to competition from cheaper foreign labor — and there’s a streak of anti-immigration populism running through the Democratic Party’s rank and file in many regions of the country.

These Democratic divisions were a significant reason the Bush-era push for comprehensive immigration reform foundered repeatedly. It wasn’t just that conservative Republicans rebelled against the White House-led effort to create a path to citizenship for illegal immigrants. It was that the Democratic leadership wasn’t eager to deliver the votes for a measure that could split their own party along lines of race and class.

What was true in Bush’s second term will probably be true in a hypothetical second Obama term as well. There might be a bipartisan coalition for a relatively limited measure like the Dream Act, which provides a path to citizenship for college graduates who were brought to America as minors. But if Jeb Bush Republicans and Obama Democrats try to fast track a more comprehensive bill, they will be reminded that there are other sorts of Republicans and Democrats, and that bipartisanship cuts both ways. Even if the president wins re-election, the populist coalition that opposes amnesty may still be as large as — if not larger than — the elite coalition that supports it.