Some constitutional language is necessarily open-textured, as when it forbids the “establishment” of religion or “unreasonable” searches, or when it guarantees the “free exercise” of religion, “due process” and “equal protection” of law. There is, in Chief Justice Warren Burger’s phrase, “play in the joints” of the Constitution.

The Framers, however, favored precision when it is possible and necessary, as in the appropriations clause: “No money shall be drawn from the treasury, but in consequence of appropriations made by law.” This defines Congress’s core power, control of the government’s purse. James Madison called it “the most complete and effectual weapon” that the House of Representatives possesses “for obtaining a redress of every grievance, and for carrying into effect every just and salutary measure.” Come Tuesday, the U.S. Court of Appeals for the District of Columbia Circuit will hear oral arguments about whether this weapon is still effectual, or whether presidents can effectively nullify it, thereby substantially reducing Congress’s significance and radically shifting in the executive branch’s favor the Framers’ intended equilibrium in the separation of powers.

Early in 2019, the political branches were at daggers drawn. Disagreement between the president and Congress about funding a border wall had resulted in the longest government shutdown in U.S. history, and then a deal: President Trump, who had requested $5 billion for his wall, grudgingly accepted what Congress grudgingly offered: $1.375 billion. Then Trump reneged.

The third of his four (so far) fungible chiefs of staff vowed, with the rhetorical swagger favored by the rhinestone cowboys in this White House, that the wall would be built “with or without Congress.” Trump began diverting for his wall money that Congress had appropriated for other uses — money that Congress had explicitly refused to provide for a wall.

Technically, Tuesday’s arguments will concern whether the House of Representatives has standing to seek judicial relief when a president violates the appropriations clause. Practically, the arguments will concern whether Congress has, as the Framers intended, a serious, indeed, controlling role in the nation’s governance.

The House argues that, unlike constitutional provisions empowering Congress to enact legislation pursuant to its enumerated powers, the appropriations clause prohibits presidents from spending money not appropriated by both houses of Congress. It does not say presidents can spend money unless doing so is specifically forbidden by Congress.

Some members of the D.C. Circuit might be inclined to say courts should steer clear of such interbranch tussles — that the House should instead use the “political tools at its disposal” to defend its interests. But its nuclear weapon, so to speak, can be its refusal to appropriate, even to the point of shutting down the government. It used this a year ago to no avail. The weapon achieved something worthless: this president’s promise.

The Trump administration first argued that even the House and the Senate acting together never have standing to sue to remedy an institutional injury. The almost-as-flimsy reed on which the administration now leans its case is the contention that the House cannot bring a suit without the Senate’s concurrence. Never mind that this is currently impossible because the Senate is controlled by Republicans who are controlled by the president, whom they fear more than they value their institution.

There are ample precedents of courts adjudicating interbranch disputes. Besides, as James Wilson stressed during the 1787 Constitutional Convention, the federal purse has “two strings” that “both houses must concur in untying.” Because both houses must agree on appropriations, each house can veto spending. Given that the Framers intended each house to have independent power over appropriations, the House argues, it follows that “a single chamber of Congress has standing where, as here, it seeks to protect an institutional power committed to it independent of the other chamber.”

In his 1833 “Commentaries on the Constitution of the United States,” Justice Joseph Story, then serving on John Marshall’s Supreme Court, wrote that without Congress’s control of appropriations, “the executive would possess an unbounded power over the public purse” and “might apply all its monied resources at his pleasure.” In bicentennial year 1976, the Supreme Court held that “the expenditure of public funds is proper only when authorized by Congress.”

In 2012, the D.C. Circuit held that the appropriations clause is a “bulwark” of the separation of powers. On Tuesday, the court, the nation’s second-most-important, will revisit all this in a case that is probably en route to the most important court, which sits about 1,000 yards away, and can stand athwart presidential overreaching.

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