When President Obama declared Friday that “there will be costs” for any Russian intervention in Ukraine, you could hear the laughter emanating from the Kremlin — followed by the sound of Russian military vehicles roaring into Crimea and seizing control of the peninsula.

“Costs?” Vladi­mir Putin must have thought. Just like the “costs” Obama imposed on the Assad regime in Syria?

Just last year none other than Putin helped Obama get out of his pledge to impose costs on Bashar al-Assad’s government for crossing his “red line” and using chemical weapons on its people.

In August 2012, Obama issued a similar warning to Syrian officials, warning that Assad would face consequences if “we start seeing a whole bunch of chemical weapons moving around or being utilized.” Assad responded by moving and using his chemical weapons — not once but 14 times beginning in December 2012, just four months after Obama declared his red line.

Obama did nothing.

Then Obama began backing away from his declaration, saying, “I didn’t set a red line. The world set a red line.” But when he went to the world and asked them to join him in enforcing “their” red line, the British Parliament voted no and NATO declined to help. Soon, the administration was lowering expectations. A U.S. official was telling the Los Angeles Times that any U.S. strike would be “just muscular enough not to get mocked.” Secretary of State John Kerry declared that any strike would be “unbelievably small” and would not really constitute “war.” Then Obama decided he needed to go to Congress and get approval for his “unbelievably small” strike. And when it became clear that he did have the votes, in stepped Putin to rescue Obama from an embarrassing defeat by offering a deal to have Syria disarm.

Obama jumped on the Russian-engineered face-saving way out. As soon as the deal was announced, Syrian officials promptly declared it “a victory for Syria, achieved thanks to our Russian friends.” To rub salt in the wound, Putin lectured the president in a New York Times op-ed about the dangers of American exceptionalism.

It was one of the most embarrassing and emasculating episodes in the history of U.S. foreign policy.

In the wake of this debacle, Obama is now warning Putin — the man who saved him from his promise to impose costs on Assad — that he’s going to impose costs on Putin for his intervention in Ukraine? Did he really expect Putin to take him seriously?

Putin believes Obama does not have the intestinal fortitude to stand up to him in Ukraine. He thinks Obama will talk tough and then look for a way out — just like he did with Assad. He also knows that without American leadership to stiffen their spines, our European allies (who depend on Russian natural-gas imports) will not impose any real or lasting consequences on Russia either. Putin calculates that he can do what he wants in Ukraine, and the whole unpleasantness will blow over in a few months.

Kerry fumed on CBS’s “Face the Nation” this weekend: “Russia is in violation of its obligations under the U.N. charter, under the Helsinki Final Act. It’s in violation of its obligations under the 1994 Budapest agreement.” But KGB thugs like Putin are not deterred by pieces of parchment. They are deterred when the United States projects strength and resolve.

Today, America is projecting weakness. Obama’s failure to enforce his red line in Syria projected weakness. His constant talk of withdrawal and ending wars so we can focus on “nation-building here at home” projects weakness. His decision to gut the U.S. defense budget and reduce the Army to pre-World War II levels projects weakness.

When your adversaries believe you are weak, they are emboldened to act — and prone to miscalculate. Putin believes there will be no real costs for his intervention in Ukraine because there were no costs in Syria. He knows the Obama Doctrine is to do just enough “not to get mocked.” If he is proved right, it will have consequences far beyond the Crimean Peninsula. A failure to impose costs on Russia will further embolden adversaries from Beijng to Pyongyang to Tehran — all of whom are measuring Obama’s resolve in Ukraine, just as Putin measured Obama’s resolve in Syria and found it lacking.

The lesson of history is clear: Weakness is provocative. And symbolic gestures and strongly worded statements are not going to get Russian troops out of Ukraine.

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