He's there to overthrow the status quo & "political correctness" like fascists do. The only way he can do that is go nuclear. Fulfil the forefathers meaning finish the Nazi mission. He may indeed be the last president of the USA as was known before he was elected. USA will no longer be a superpower. It's gonna be littered with poverty, tragedy, destruction, some horrendous atrocities.
"Drain the swamp"
The term alludes to the historical drainingof swamps to keep mosquito populations low to combat malaria.
In other words he idealizes mass culling. A man that age doesn't care for integrity and policies. He's after immortality & eugenics. Kill the poor, harvest their organs for science, organ donations, rejuvenation policies, resources more plentiful for the elites. Putin is obsessed with immortality & they have that commonality in their souls.