It's a winner take all two-party election where a 3% swing in sentiment results in a complete blowout.
Generally one of the two participants wins those.
There's a really serious systemic problem with the party that chose him in its primaries, and there is nothing to prevent it from happening again, but my point is that a 49.8% mandate given the circumstances is... Well, it's not one of overwhelming sentiment.
The US had the smallest drop in support for an incumbent party.