From Fallujah to Ferguson, from Mosul to McAllen, we are inundated with crises at home and abroad. Meanwhile, a genuine constitutional crisis looms on the horizon, yet far too many journalists are treating it like just another partisan political debate.

The looming crisis concerns federal immigration policy, and President Obama’s threat to dramatically change that policy via executive fiat. Throughout the summer, the White House has been dropping hints that President Obama is poised to grant amnesty to several million illegal immigrants all by himself. Earlier this week, the New York Times confirmed that “the process of drafting what will likely be the only significant immigration changes of his presidency — and his most consequential use of executive power — has been conducted almost entirely behind closed doors, where lobbyists and interest groups invited to the White House are making their case out of public view.”

Your democracy at work!

Contrary to what President Obama’s defenders have argued, there is no serious legal precedent for a gigantic unilateral immigration amnesty. (Some analysts have cited President Carter’s 1977 pardon of draft dodgers, but the comparison falls apart rather quickly.) For that matter, as I’ve noted in previous posts, Obama himself has admitted — as recently as last November, but also last September and in March 2011 — that the Constitution prohibits him from simply decreeing a mass amnesty. In the president’s own words: “With respect to the notion that I can just suspend deportations through executive order, that’s just not the case, because there are laws on the books that Congress has passed.”

Of course, Obama ignored those laws two years ago when he — unilaterally — launched his Deferred Action for Childhood Arrivals (DACA) program, which granted “temporary” amnesty to a large number of illegal immigrants who first came to the United States as minors. Yet even after DACA took effect, Obama rejected the idea of expanding it to include illegal immigrants who arrived as adults. In September 2013, he told Telemundo that such a major expansion of DACA would amount to “ignoring the law in a way that I think would be very difficult to defend legally. So that’s not an option.”

Now, apparently, it is an option.

Obama’s unilateral-amnesty threat has received pushback, not just from anti-amnesty conservatives, but also from pro-amnesty liberals. For example, the Washington Post editorial board has urged Obama not to “tear up the Constitution.” Even liberal blogger Jonathan Chait — who in 2012 declared Obama “easily” the greatest U.S. president in more than half a century — has raised concerns about the proposed immigration scheme. “I fully support Obama’s immigration policy goals,” Chait wrote last week. “But the defenses of Obama’s methods seem weak and short-sighted.” Among elected Democrats, Senator Kay Hagan of North Carolina has said that immigration “should be addressed legislatively and not through executive order,” and Senator Mark Pryor of Arkansas has stressed that partisan gridlock “doesn’t give the president carte blanche authority to sidestep Congress when he doesn’t get his way.” (Both Hagan and Pryor are up for reelection this year.)

Unfortunately, and not for the first time, President Obama appears to have given up on using the legislative process to achieve his objectives. A unilateral mass amnesty would presumably be defended on the basis of “prosecutorial discretion,” which has become the administration’s catch-all justification for executive overreach. Law professors John Yoo and Robert Delahunty have shown where such abuses of power might lead. Liberals should ask themselves how they would feel if a Republican president argued that, because of insufficient resources at the IRS and the EPA, he was unilaterally suspending the enforcement of certain tax and environmental laws.

In short: President Obama’s decision to move forward with or pull back from an executive mass amnesty could mark a watershed moment in American politics. Mark Krikorian, executive director of the Center for Immigration Studies, puts it this way: “The proposed expansion of DACA to amnesty perhaps ten times as many illegal aliens would represent a decisive change in our political system, preserving the forms of representative government but dispensing with its substance.”