DAVID BYLER: Five Theories on Trump’s Stable Approval Rating.

Here’s the first theory:

Trump’s 40 percent approval rating might represent something close to his floor. On Election Day 2016, 37.5 percent of voters viewed candidate Trump favorably, yet he won 46 percent of the vote. Since then, Trump may have lost some of those general election voters by pushing an unpopular health-care bill (or through some other actions they disapproved of), but this 40 percent approval rating represents party stalwarts sticking with him.

The polarization theory comes with a few predictions about the future. As long as there aren’t any truly out-of-the-ordinary events (e.g. a terrorist attack, a recession, a historic economic boom, impeachment, etc.) Trump’s approval rating will stick within a relatively narrow band. He won’t lose his loyalists but he also won’t convert many outside that group. This theory doesn’t rule out a Democratic midterm wave or a second Trump term, but it does suggest that there are some guardrails that keep either party from scoring the sort of landslide wins we saw in the last century.

Barack Obama enjoyed this very same phenomenon (albeit with a slightly higher floor) during his two terms, although he had the advantage of a much friendlier press — to say the very least.