Secretary of State John Kerry is warning Iran that the United States will not "stand by" as violence erupts in Yemen.

To which the Iranians, who have had ample opportunity to take John Kerry's measure and that of his boss, are likely thinking: Oh, yeah?

President Obama seems strangely removed from the turmoil he in part has created; mullahs are leading chants of “Death to America,” but our wise president is above taking note of such foolishness. The mullahs know that–pace John Kerry's recent words–the U.S. will stand by no matter what the Islamic dictatorship does in Yemen.

What accounts for President Obama’s passivity (often punctuated by such statements as the one Mr. Kerry has just uttered) in the face of disaster? Daniel Henninger has a good analysis of "The Incredible Obama Doctrine" in today’s Wall Street Journal. It is today's must-read. Here is a nugget:

“You asked about an Obama doctrine,” Mr. Obama said. “The doctrine is: We will engage, but we preserve all our capabilities.”

In nine words, Mr. Obama explained what has been going on the past six years, culminating in what we now see is the nucleus of the Obama worldview, an accommodation with Iran.

The corollary of the Obama Doctrine, as the president explained, is that if engagement with a hostile power turns dangerous, everyone in the world knows that U.S. “military superiority” will emerge and prevail. In case of emergency, Uncle Sam will break glass.

Mr. Obama then offered an example of how this would work—U.S. support for Israel:  “What we will be doing even as we enter into this deal is sending a very clear message to the Iranians and to the entire region that if anybody messes with Israel, America will be there.”

This statement, and indeed the Obama Doctrine, is a hoax.

Set aside that “messes with Israel” and “America will be there” are phrases with no real operational meaning.

“America will be there” could mean that if someone set off a nuclear backpack bomb in Tel Aviv, where the Obama administration would be the next day is on New York’s east side, condemning the attack in a U.N. Security Council resolution.

Henninger says that the tendency to personalize our foreign policy mess, as former vice president Dick Cheney did in calling President Obama the worse president ever, and as Lindsey Graham did in saying Hillary Clinton would be better (and as I did at the top of this item), gets it wrong. Henninger writes:

It is a mistake to suggest U.S. foreign policy is weak only because Barack Obama is running it. On the cusp of a presidential election, the more pertinent question is whether U.S. foreign policy is weak because a Democrat is running it.

Would U.S. foreign policy be substantively different if run by a President Clinton or President Warren or President O’Malley?

Mr. Obama’s “doctrine” is essentially that if something bad happens, he will send in the 82nd Airborne Division. But he won’t. No Democrat whose view of large-scale U.S. military power was formed by the Vietnam War or the Iraq War will do that. Other than aerial bombardments, using the full range of U.S. military assets ended for Democrats with the Johnson presidency.

Joe Lieberman, Henninger recalls, was the last Democrat to believe in American power, and he lost his Senate seat precisely because of that. The presidential campaign of 2016 is going to be a time to consider whether the U.S. should assert its authority in the world.

On the GOP side, maverick Senator Rand Paul, who announced this week, has always represented the non-interventionist wing of the GOP. This will give the Republicans an interesting debate. But a specter haunts any discussion of American power: once lost, can it be regained? The U.S. has been taken down a peg or two—or dozens of pegs—in the last six years. It is by no means certain that the World War II Pax Americana will ever be restored. If this is so, it will follow that President Obama fundamentally has transformed not just the U.S. but the world.