WASHINGTON — For a man who is often so Hamlet-like he seems he should be attending meetings in a black velvet doublet and whose Syria policy in particular seems to have been defined primarily by actions not taken and decisions not made, Barack Obama made one of the most profound and momentous decisions of his presidency on Saturday.

By announcing that he would require congressional approval before taking action against Syria’s regime for gassing its own people, he took a step that seemed certain to have multiple, potentially profound ramifications. Here are just five:

1) A Syria attack isn’t a sure bet.

Military action against Syria that seemed a “certainty” on Friday is no longer assured. And if air strikes do take place, their delay — despite Obama’s protestations to the contrary — make them likely to be less effective. The far right and left of the parties are disinclined toward intervention. The more hawkish are disinclined toward actions that are too limited. And many Republicans are disinclined to do anything that might help Obama.

If the administration persuades Congress to support military action, it will be seen as a victory for the president, to be sure. But it may also have given the Assad regime another two or three weeks to redeploy assets and hunker down — so that the kind of limited attack currently envisioned has even more limited consequences.

2) Red lines ain’t what they used to be.

The president has hemmed and hawed regarding his supposed “red line” on chemical weapons use yet again, further undercutting his credibility. Taking action seemed the only way to restore a sense that the president was a man who meant what he said. But then, late last week, as Britain balked at supporting Washington and domestic public opinion was seen to oppose any U.S. involvement in Syria, a spirit of hesitation seemed to grab the administration, culminating in Saturday’s bombshell.

3) He’s now boxed in for the rest of his term.

Whatever happens with regard to Syria, the larger consequence of the president’s action will resonate for years. The president has made it highly unlikely that at any time during the remainder of his term he will be able to initiate military action without seeking congressional approval. It certainly appears to be more in keeping with the kind of executive-legislative collaboration envisioned in the Constitution.

But whether you agree with the move or not, it must be acknowledged that now Obama has set this kind of precedent — and for a military action that is exceptionally limited by any standard — it will be very hard for him to do anything comparable or greater without again returning to the Congress for support.

4) This president just dialed back the power of his own office.

Obama has reversed decades of precedent regarding the nature of presidential war powers — and he is transferring greater responsibility for U.S. foreign policy to a Congress that is more divided, more incapable of reasoned debate or action, and more dysfunctional than any in modern American history. The president’s own action in Libya was undertaken without such approval. So, too, was his expansion of America’s drone and cyber programs. Will future offensive actions require Congress to weigh in? We live in a volatile world; sometimes security requires swift action. The president still legally has that right, but Obama’s decision may have done more — for better or worse — to dial back the imperial presidency than anything his predecessors or Congress have done for decades.

5) America’s international standing will likely suffer.

As a consequence of all of the above, even if the president “wins” and persuades Congress to support his extremely limited action in Syria, the perception of America as a nimble, forceful actor on the world stage and that its president is a man whose word carries great weight is likely to be diminished. Not only is post-Iraq, post-Afghanistan America less inclined to get involved anywhere, but when it comes to the use of U.S. military force (our one indisputable source of superpower strength) we just became a whole lot less likely to act or, in any event, act quickly.

A final consequence of this is that it seems ever more certain that Obama’s foreign policy will be framed as so anti-interventionist and focused on disengagement from world affairs that it will have major political consequences in 2016.

The question will be whether a centrist synthesis will emerge that restores the idea that the United States can have a muscular foreign policy that remains prudent, capable of action and respects international laws and norms.

Almost certainly, that is what President Obama would argue he seeks. But I suspect that others, including possibly his former secretary of state, may well seek to define a different approach.

And just imagine Clinton vs. Rand Paul in the general election.

David Rothkopf is CEO and editor-at-large of Foreign Policy.