Its paid out of current years taxes. It's never going anywhere until they replace it with something better like the money you pay in going to your retirement plan of choice and the government matches 10% or something. It's never going to be insolvent. It will require taxes to go up a few percent.
So according to the constitution a judge has to sign a warrant to require you to show up. It's called a subpoena. Congress doesn't have the power to do this nor do they have the power to conduct any kind of hearing with legal authority except in the case of impeachment. So I don't see this going anywhere.
