Reagan.

Arguably, this 'steady plodder of a president' was the most successful politician of all time.
Portrayed - typically - as 'terminally stoopid' by the usual suspects, his successes were the stuff of legend.
Put to one side the runaway success of his 'Reaganomics' and let us concentrate on his external Realpolitik.
He surrounded himself with people who were much more talented than the average entourage.
He won the heart and mind of Margaret Thatcher - a most formidable ally.
He entered into a largely secret and highly significant alliance with the anti-communist Vatican and in particular, Pope John-Paul the Second.
He was behind the Star Wars fraud which placed the final nail into the soviet coffin.
All in all, this man damned as a 'third rate actor' by Democrats and assorted lefties was the single largest factor in the downfall of communism, the USSR and all of its satellites thus also giving the West a massive 'peace dividend'.