A couple of weeks ago, Sean Hannity, the conservative political commentator, juxtaposed for the viewers of his Fox News show a picture of a helmeted Barack Obama peddling a bicycle and a bare-chested Vladimir Putin astride a horse.
It was a cartoonish representation of the question that is being asked by less overtly partisan observers in Washington: Has the U.S. president's less strident approach to international policy turned America into a pushover?
For many in Washington, the inability of the United States to deter Russia from interfering in Ukraine's internal affairs is the latest indignity on a list that includes the civil war in Syria, China's apparent comfort in expanding its military reach in the Pacific, and the fatal attack on the American mission in Benghazi, Libya.
A former U.S. intelligence officer, who spoke on the condition of anonymity because he only recently left the Obama administration, said Mr. Putin's move on Ukraine shows there were "a lot of misguided expectations" and that a reassessment of the American approach to Russia was in order.
"No one expected things to turn out this way," the former official said.
John McCain, the Arizona senator who lost to Mr. Obama in the 2008 presidential election, blamed Mr. Obama directly. "There is a perception of American weakness all over the world," Mr. McCain said in an interview with Bloomberg Television Monday.
The second-guessers say the West's vocal support of the Ukrainian opposition may have provoked Mr. Putin, a mercurial leader who shouldn't have been underestimated. The U.S. perhaps could have put him off orchestrating a referendum in Crimea with quieter diplomacy, deploying a high-level envoy to defuse the situation.
"Crimea is a done deal," said Fen Osler Hampson, director of the global security and politics program at the Waterloo, Ont.-based Centre for International Governance Innovation. "It is going to be very hard to get it back."
However, it's far from clear that there was reasonable response available to Mr. Obama. Prof. Hampson, who teaches at Carleton University in Ottawa, agrees with the impression that Mr. Obama's approach to Russia was to "speak softly and carry a twig." Yet he says European leaders bear most of the responsibility because they failed to take Ukraine seriously enough.
The biggest difference between Mr. Obama's foreign policy and that of his predecessor, George W. Bush, is that he has made clear that he doesn't see himself as the world's beat cop. Whatever geopolitical tension that existed between Russia and Ukraine reasonably was a matter for the European Union to manage. Mr. Bush's bravado on the world stage did nothing to stop Mr. Putin from invading Georgia in 2008 and taking control of Abkhazia and South Ossetia.
"If you define effective as the president of the United States can do something to change Russian behaviour in Ukraine, then [Mr. Obama] has not been effective," said Willis Sparks, a New York-based analyst at the Eurasia Group, a consultancy that assess political risk for banks, corporations and government agencies. "That is not a reasonable expectation, given the fact that Ukraine is approximately 7,500-times more important to Russia than it is to the United States."
On Monday, the U.S., the EU and Canada moved to freeze the international assets of a group of Mr. Putin's "cronies." The Russian government also signalled there could be a negotiated solution with the West. Moscow's insistence that the Crimean referendum be recognized is a non-starter, but the suggestion that Ukraine remain a neutral state, is seen as possible grounds for talks. The country's interim prime minister, Arseniy Yatsenyuk, said last week that Ukraine wants to be both part of Europe and a friend to Russia.
In any case, Mr. Obama left himself the option to go after the assets of yet more Russian and Ukrainian individuals, a strategy that has proven successful in recent years in bringing North Korea and Iran to the negotiating table. Mr. Sparks points out that the U.S. and the EU now are galvanized to ensure Ukraine receives an economic lifeline from the International Monetary Fund, something that might otherwise have been subject to delay because of the IMF's misgivings about the country's track record of corruption and broken promises related to previous loans.
Barry Pavel, a former defence policy adviser in the administrations of Mr. Bush and Mr. Obama, said it was "ridiculous" to assert Mr. Obama could have blocked Mr. Putin's opportunistic move on Crimea. The test of the U.S. President's foreign policy could instead be his ability to dissuade Mr. Putin from attempting to claim more predominantly Russian-speaking areas of eastern Ukraine.
"I know pretty well that he does not fear Obama regarding other potential next steps," said Mr. Pavel, who now is director of the Brent Scowcroft Center on International Security at the Atlantic Council, a thinktank in Washington. "That's where I'm quite worried."