On February 22, popular protests led to the fall of the pro-Russian government of Viktor Yanukovych in Kiev. On February 27, in response to this setback, President Vladimir Putin sent forces into Crimea to seize it from Ukraine. On March 19, President Barack Obama delivered his response. He reassured Putin, “We are not going to be getting into a military excursion in Ukraine.” Obama added, “What we are going to do is mobilize all of our diplomatic resources to make sure that we’ve got a strong international coalition that sends a clear message.”

The message is clear. The problem is its content. Obama certainly isn’t sending the message that Colin Powell, after the Cold War, wanted America to send: “Superpower lives here.” Obama’s message, by contrast, is: “Superpower once lived here. No forwarding address.”

Putin understands Obama’s message. He knows he’s won Crimea. The question is whether he’ll win Ukraine.

He thinks he will. He’s dealing with the Obama administration, after all. He looks at the U.S. withdrawal from Iraq and Afghanistan, he witnesses the failure to enforce the red line in Syria and the subsequent successes of his friend Assad, he chortles at the relaxation of the sanctions on Iran and the desperate desire to cut a nuclear deal, and he sees Obama’s defense cuts. And he reads the New York Times, where David Sanger reports, “Mr. Obama acknowledges, at least in private, that he is managing an era of American retrenchment.”

So Putin sees retrenchment. Putin sees retreat. And Putin sees that Obama is unlikely to reverse course.

In late 1979, with the seizure of American hostages by Iran and the Soviet invasion of Afghanistan, President Jimmy Carter was mugged by reality. Carter then tried, however haplessly, to change direction. But Barack Obama is no Jimmy Carter. Will Obama increase defense spending, as Carter did? Is he likely to launch a military excursion, as Carter did, over the objection—and then resignation—of his dovish secretary of state?

Carter, whatever his problems, was more hawkish than most in his party. In this he followed in the footsteps of every other Democratic president in the past century. Until Barack Obama.

It’s been a bit bewildering, even disorienting, to watch Obama get mugged by reality and refuse to press charges. But of course he doesn’t want to press charges. He doesn’t believe in an international system in which the American role is to lead. Former Saudi intelligence chief Turki al-Faisal was asked by the Financial Times recently about Putin and Obama. He explained: “While the wolf is eating the sheep, there is no shepherd to come to the rescue of the pack. This is where we find ourselves today.”

Indeed it is. In the New York Times, Sanger comments, “History suggests that such eras [of retrenchment]—akin to what the United States went through after the two world wars and Vietnam—often look like weakness to the rest of the world.” Retrenchment looks like weakness because it is weakness. And the consequences of such eras of weakness aren’t happy.

What is to be done? Congress needs to push the administration in the right direction as much as possible. Foreign policy experts need to propose sound measures—to ensure, for example, that the loss of Crimea isn’t followed by the loss of Ukraine—in the hope that President Obama might be pressured to embrace them.

More broadly, though, the opposition—which one hopes will come to include some liberals and some Democrats—has to articulate a foreign and defense policy of resolve and strength. Allies and enemies around the world will read the American situation differently if they think the American collapse of will is bipartisan than they will if they see that it is not. Pro-Western forces around the world may be able to maneuver and to hang on if they receive a clear message that the cavalry is coming to the rescue on January 20, 2017.

So it’s important to mount a vigorous opposition to Obama’s foreign and defense policies. It’s important to propose serious alternatives. It’s important not just for the sake of intellectual honesty and political clarity. It’s important because what the opposition says now can make a difference in the world over the next three years.

It will still be a rough time. America can’t be strong with a president committed to weakness. But the prospects for a restoration of American strength will be brighter, the challenges of 2017 will be less daunting, if the opposition today stands clearly and unequivocally for American strength and leadership, and—dare one say it?—for American greatness.