The fact that Trump has lost the greatest number of supporters in red states is perhaps the clearest indication yet that he is losing ground among some form of his base, if you think of his base as those who voted for him in November
Well … with a couple caveats. It’s possible that the polls are merely underestimating Trump in these red states. Trump most outperformed his polling in 2016 in red states. Maybe that’s happening again. That said, he also beat his polls in Midwestern states, and he’s holding his own (relatively speaking) there, which argues that his red-state decline can’t be written off only as polling error.
But even if this polling is perfect, Trump still might not have lost ground, per se.