Is today the day Donald Trump falls back to earth?

After a weekend in which Ted Cruz managed to slow Trump’s momentum, today’s contests in Hawaii, Idaho, Michigan, and Mississippi will be watched closely for signs that Trump has finally hit a wall. Trump is expected to win Michigan, but the other contests are up in the air, as Politico explains:

A relative lack of polling adds unpredictability to Tuesday’s votes. While Michigan has been heavily surveyed, Hawaii has gone uncovered, and sparse polls in Mississippi and Idaho are now out of date. Trump had large leads in past surveys, but they were conducted before Marco Rubio and several super PACs went all-out against Trump, before two raucous anti-Trump debates and before his losses to Cruz on Saturday.

A new ABC News/Washington Post poll appears to confirm the notion that Trump has hit a ceiling. Furthermore, the poll shows Trump losing to both Cruz and Rubio in head-to-head match-ups. But if Trump sweeps today’s primaries, we’re back to the old narrative of Trump being unstoppable.