He'd be 85. Americans' tolerance for geriatric leadership will only decrease further if Biden gets a second term, and is arguably already waning. We may be locked into a Trump v Biden Oldster Battle in 2024, but the only way the GOP hangs on to Trump this long is if he stays centrally relevant to their appeal long enough to lose either the primary or the election for 2 more election cycles, in which case they'd never field him again anyway. I'm normally fairly conservative making pronouncements, especially about prerennial rule exception Donald Trump, but there is NO WAY this could ever realistically happen.