Executive discretion in spending is legitimate
Let me be direct about what the Constitution actually says, and what it does not. Article I grants Congress the power of the purse — full stop. When Congress appropriates funds for a transit project and the President simply declines to spend them, that is not executive discretion; that is the executive branch nullifying a legislative act by inaction. I built the Treasury from nothing, and I understood that executive energy means vigorous *execution* of the law, not the power to unmake it by sitting on it. The Framers gave the President a veto for a reason — use it before the bill passes, not after the money is committed. An executive who impounds appropriations he dislikes has not exercised discretion; he has seized a second veto the Constitution never granted him. Infrastructure is the sinew of commerce. These are not abstract funds — they are the roads and rails by which a national market breathes. Freeze them at your peril, and at the Republic's.
Congress alone commands the purse
The answer is not close. Article I, Section 9 could not be plainer: no money shall be drawn from the Treasury except in consequence of appropriations made by law. The power of the purse is the legislature's most essential tool — it is the very mechanism by which an elected assembly maintains its hold over an executive who might otherwise govern by will alone. When Congress passes an appropriation, it does not offer the executive a suggestion; it issues a legal command. An executive who may simply decline to spend what the legislature has lawfully directed has, in practical effect, absorbed the appropriating power into himself — collapsing two branches into one, precisely the consolidation the separation of powers exists to prevent. Whatever a president's policy preferences regarding transit or any other program, the remedy is to return to Congress and seek repeal, not to nullify the statute by inaction. Impoundment is not discretion; it is usurpation.
States should fund infrastructure, not feds
The present controversy, however it resolves in court, exposes a deeper constitutional disorder: the federal government has so thoroughly extended its financial arm into what were always local and state concerns that a President's refusal to spend becomes a crisis affecting commuters, bridges, and tunnels from New York to California. Had the framers' design held — had the states retained the fiscal and sovereign authority to build, maintain, and fund the works their citizens actually use — no single executive's preference, however arbitrary, could hold an entire transit network hostage. The cure is not simply to force a reluctant President to spend; the cure is to restore to states the taxing capacity and the responsibility to fund their own infrastructure, so that the citizens of Virginia answer to Richmond and the citizens of New York answer to Albany, not to whichever administration happens to occupy the executive mansion in any given season.