It's clear that this is an authority that the president does not possess. The President does not have unilateral authority to impound funds. Congress has the power of the purse.

It's clear, but political power only exists if it's used. If congress grants this power to the executive, they render themselves all but irrelevant. They'd be a rather expensive and unattractive claque.

No, its clear that it is authority the President does not have under the Constitution, and even when Congress tried to give the President a small fraction of this power in the 1996 Line Item Veto Act, that Act itself was found to be unconstitutional: its power the President doesn't have under the Constitution and could not Constitutionally be given.

Apparently he can for a short period, yes, according to MSM.