While Trump enjoys a steady, albeit unspectacular support of 77% of Hoosiers in the Ball State poll, the real fall off is with non-Republican voters. As the Morning Consult poll shows, any support Trump had among Democrats during his election is long gone and independent voters have also turned sharply against him.
Trump supporters have long forgotten that Trump did not even win the popular vote, and barely eked out an Electoral College win, against the weakest candidate the Democratic Party has ever nominated. Trump's 35% base only got him half way around the track. It was the anti-Hillary Clinton voters who put him over the finish line. Unless the Democrats are dumb enough to nominate Hillary again, any chance President Trump has of getting re-elected are slim and none.