It could be stable in the US. The basic idea behind Keynesian economics is: during contractions, decrease taxes and increase spending; during expansions, increase taxes and decrease spending. Doing this helps smooth out business cycles, promotes steady growth, and collects revenue for the government.
The problem is, as we've seen, our government is cutting taxes and raising spending no matter where we are in the business cycle. That's a very easy problem to solve, if there is the political will, but right now, there isn't.