Conventionally, at least in Britain, you just say "Peace in our time" (or more correctly "Peace for our time") to invoke this idea. That's what Prime Minister Neville Chamberlain said after he landed in Britain with signed agreement from Hitler that there would be no war.

But I suppose that might be unfamiliar to American readers as they did not enter the war at the beginning, and "Peace for our time" was invoked in a different context by JFK.