Very unusual fault lines are hardening in Congress on the most consequential foreign policy dispute of the summer, with senior lawmakers in both parties taking opposite stances about whether aid to Egypt should be withheld if civilians aren’t quickly put back in charge.

The debate poses the classic question of whether it is more important for United Sates foreign policy to focus on advancing American democratic principles around the word, which would mean cutting off the aid, or to put a premium on protecting the country’s current economic and military objectives, which would mean keeping the money flowing.

The discussion is moot, however, as long as President Barack Obama holds to the view that what’s happened in Cairo during the past week does not amount to a coup d’etat, which was the preliminary position the White House staked out Monday. A law expanded 18 months ago compels the administration to withdraw aid from any country where the military has seized power by force from a democratically elected government. It doesn’t permit the president to waive the rules, but neither does it provide Congress with any legislative vehicle for countermanding his decision.

The author of the law is the most senior member of the president’s party in the Senate, Democrat Patrick J. Leahy of Vermont, who also chairs the Appropriations panel that doles out foreign aid. Within hours of the ouster of Mohammed Morsi’s Muslim Brotherhood-led government last week, he said the statute obviously applies to Egypt and that this year’s $1.5 billion should be held in abeyance at least until elections restore democratic rule and the generals step out of the way.

Both parties’ most influential members on Senate Armed Services, Democratic Chairman Carl Levin of Michigan and Republican John McCain of Arizona, said Monday that they agree with that position, although they conceded there was probably not a majority at the Capitol to move a bill reversing the administration’s position. Rand Paul of Kentucky, the harshest GOP critic of Egypt in the Senate, vowed to renew his efforts to halt the aid — more than three-quarters of which goes to military hardware.

But the president has a seemingly more forceful collection of congressional allies on his side starting with Speaker John A. Boehner, who told reporters Monday that Egypt’s military leaders deserved praise for doing “what they had to do in terms of replacing the elected president.” The Republican who chairs the House Intelligence Committee, Mike Rogers of Michigan, said cutting off aid now would make an unstable situation significantly worse. So did the Democrat who chairs Senate Foreign Relations, Robert Menendez of New Jersey, because “you will take an economy that is already floundering and probably drive it into chaos.”

In essence, the first step for Congress would be to clear legislation, and persuade Obama to sign it, to prevent the cutting of checks for any aid appropriated for this fiscal year that hasn’t already been delivered. Given the already apparent split in both parties, and the short time available, that’s clearly a legislative non-starter. But the political dynamics don’t look much easier for an effort to limit aid to Egypt as part of the appropriations process for fiscal 2014, which begins in October.

The administration has not made a formal, legal determination about whether the military takeover meets the law’s formal definition of a coup or whether, as the generals say, they acted in response to a popular uprising that was quickly turning toward chaos. State Department lawyers have no timetable for doing so. In the interim, the administration has the power to slow-walk the aid delivery as a way of prodding the military to move more quickly to restore civilian rule.