> and they can't or won't do it

Instead of blaming Congress, perhaps blame democracy.

Voters loath austerity, and they support spending.

Watch the experiment happening live in New Zealand elections. Our incumbant conservative party (National) is aiming for a budget at about 30% of GDP. Our progressive party (Labour) wants to increase taxes and increase spending to maybe 33% of GDP.

You can see if voters care about keeping spending in check, because it seems likely to be a central issue of campaigns. Although we have MMP voting so it isn't totally clear. Also note that I think most of our politicians would be seen as left-wing if looked at by anyone on the right.