giving the President numerous powers to act under the National Emergencies Act. A number of these actually give him powers to re-allocate funds already budgeted to specific projects.

They have expressly ceded their power of the purse in a number of specific instances strictly at the discretion of the President. This has happened a number of times historically.

The National Emergencies Act, as well as the follow up statutes, give the President great discretion in declaring an emergency and very few limits or restrictions on what constitutes an emergency. The term is so vague the courts could easily defer to the discretion granted by congress.

Congress can terminate a Declaration by passing an act ending it, but it would be subject to veto. Both chambers would then have to overcome the veto, requiring a super majority. Unlikely to happen, at least in my estimation.