WASHINGTON — Senator John McCain used his address to the AIPAC conference here Monday to launch a bitter attack on what he called the lack of US leadership in foreign policy under President Barack Obama.

The Arizona senator, who was defeated by Obama in the presidential race of 2008, said the current situation in Ukraine, the failure to support reformists in Iran in 2009, and the decision not to intervene in Syria after President Bashar Assad used chemical weapons against his own people, all reflected “a feckless foreign policy where nobody believes in America’s strength anymore.”

While Obama might want to believe that the Cold War is over, said McCain, Russian President Vladimir Putin does not. That’s why Putin was intervening in Ukraine, and that’s why Putin was “assisting Assad’s slaughter” of the Syrian people by sending planeloads of weaponry to Damascus.

Obama’s public flip-flop about punitive action against Assad last summer sent a message of weakness that resonated “around the world,” McCain charged.

If Assad prevails in the civil war, he said, that would “directly endanger the security of Israel.” The war was already destabilizing Jordan, he noted. “The whole situation cries out for American leadership, and I’m sorry to tell you, it’s MIA.”

On Iran, McCain urged a vote now on new sanctions to take effect if the current talks on a permanent resolution over Iran’s rogue nuclear weapons program fail. Iran has the right to peaceful nuclear energy, he stressed, but that did not require industrial enrichment capacities, a heavy water rector, sophisticated centrifuges, “and nuclear facilities dug deep into mountains.”

He lamented that “the president of the United States didn’t say a word” when domestic opponents of the Iranian regime sought support in 2009, and warned that Iran remains “categorically devoted” to the destruction of Israel.

Strikingly, McCain made no reference in his address to the Israeli-Palestinian conflict.