Just curious ... without the US to defend his approach in WWII, where would Churchill have been vis-a-vis Hitler?
Even with the US coming in to save him (props to Canada, Australia, and everyone else, but the US put up, in sheer size, more than the rest of us put together) there is simply no argument to the fact that Churchill left England a shadow of the Empire it was when he arrived (size, wealth, military power, global influence).
If you go back to WWI (where he had considerable, but not total influence on things), not just WWII, the Churchill record is even more embarrassing in terms of what he did to destroy Britian's once considerable colonial might.
History counts winners and losers very easily - where were you when you started, and where were things when you left? Churchill played the game in a way that saw his society lose 90% of the power it had by the time he arrived.
By comparison, the US played the game in a way that saw them win large for the next 50 years.
You might want to think about that when you venerate Churchill. Or when people trace back the change in US power under Bush Jr.