In last week’s budget standoff, the headlines had President Obama repeatedly “summoning” the speaker and the Senate majority leader to the White House. “Why,” my colleague David Boaz asked, “doesn’t the speaker ‘summon’ the president to what I think is the real seat of government?”

It’s a good point: Whether or not you score the budget deal as a win for the GOP, the casual way the media describes the president’s role shows how dangerously far we’ve drifted toward one-branch rule.

Congressmen of old “would have received as a personal affront” any message from the president calling on them to change their position, Massachusetts Sen. George Hoar wrote in his 1903 memoirs: “If they visited the White House, it was to give, not to receive advice.” “In a republican government,” the Federalist explains, “the legislative authority necessarily predominates,” and is therefore most to be feared.

Today, not so much. Consider the controversial “policy riders” that almost sank the budget deal. The measure defunding Planned Parenthood got most of the coverage, overshadowing important provisions aimed at restricting the Environmental Protection Agency’s power to regulate greenhouse gases.

Seizing on the Supreme Court’s 2007 ruling that the Clean Air Act’s definition of “pollutant” was broad enough to encompass CO2 — a gas essential to life on Earth — the Obama administration has begun to “legislate” global warming policy in an end-run around Congress.

Whatever your views on climate change, you ought to find it unsettling that, here and elsewhere, most of the actual “law” in this country is crafted by unelected executive-branch bureaucrats.

But that’s where we are. A few months back, the New York Times reported that some 230 health regulators had descended on Bethesda — paying double rent for office space so they could immediately begin drafting more than 300 rules implementing Obamacare. Thanks to “mega-bills passed by Congress,” the Times explained, regulators are issuing “hundreds of sweeping financial and health care regulations that will ultimately affect most Americans.”

As at home, so too abroad: having ceded its constitutional power, Congress sits on the sidelines and carps while the president wages war.

Two weeks ago — nine days after we started bombing Libya — President Obama got around to explaining why. His televised address ran more than 3,000 words, but “Constitution” never appears — and “Congress” occurs only once: a passing reference to “consulting the bipartisan leadership of Congress.”

The president’s supposed to do more than “consult”; the real “decider” is Congress. Our Constitution grants the legislature sufficient power to make talk of “co-equal branches” a misnomer.

The constitutional scholar Charles Black once commented, “My classes think I am trying to be funny when I say that, by simple majorities,” Congress could shrink the White House staff to one secretary, and that, with a two-thirds vote, “Congress could put the White House up at auction.” (I sometimes find myself wishing they would.)

But Professor Black wasn’t trying to be funny: it’s in Congress’ power to do that. And if Congress can sell the White House, surely it can defund an illegal war and rein in a runaway bureaucracy.

If they don’t, it’s because they like the current system. And why wouldn’t they? It lets them take credit for passing high-minded, vaguely worded statutes, and take it again by railing against the bureaucracy when it imposes costs in the course of deciding what those statutes mean.

But it’s our fault as well. In the shell game of modern American governance, we’ve let ourselves become easy marks. Unless and until voters wise up and demand accountability, Congress will continue to take our money and shirk its duty.