The debt limit thus operates like the Social Securitytrust fund: it imposes an important operational restraint, and budget actions used to avoid it cannot pay for other programs.
Doubtless they want it to be strong in operational terms in conducting international trade talks, managing the budget, making and enforcing antitrust rulings, for example.
This comparison reveals the unique feature of Medicare Part A: It is the only one of these programs that allows budget savings to pay for other programs and has a trust fund with real operational teeth.