The financial time bomb no one is discussing

 The explosive growth of the national debt.

In the absence of fiscal restraint, the interest rate for servicing this debt can only go higher.  As interest rates go higher, the debt gets bigger, even if other federal spending is held constant—which it won't be.  Both Republicans and Democrats will vote for higher deficit spending, the only question is how much higher.

This path is not sustainable.  A bipartisan agreement removed the debt limit entirely, but only until next January.  The next President will have the mother of all financial calamities to deal with.