Overconfidence is going to be the downfall of Trump. The fact that his supporters believe that he is a lock for re-election is a disadvantage. Then again, they are probably counting on getting help stuffing the ballot boxes or making Democratic votes disappear.
I don't think Trump is assuming he's a lock for re-election. If he did, he wouldn't have started his re-election campaign already. The thing about Trump is, he
enjoys campaigning. That means getting overconfident is less of an issue, because the biggest pitfall of being overconfident is usually that you don't try to campaign as hard. That's what happened to Thomas Dewey, and Hillary Clinton also suffered from this - for Trump, it's less of an issue because he'll campaign hard because he
enjoys it, not because he needs to. It's like how most successful entrepreneurs keep working at their jobs long after they've retired because they want to.
But no, I don't think any Republicans are assuming Trump is a lock for re-election, since his original election was so narrow. Or if they did, they'd be really stupid to do so, but I haven't seen evidence of it yet.
