Washington: US Defence hawk Senator John McCain stressed on Monday that deployment of US military force to Ukraine remained unthinkable, but said President Barack Obama nevertheless has failed to stand up to Russian counterpart Vladimir Putin.
McCain has spent days criticising Putin`s aggression in Ukraine, Europe`s worst standoff since the Cold War, with the veteran American lawmaker arguing that Russia`s President seeks to use unrest in the key former Soviet republic as a pretext to reassert Russian dominance there.
"It`s a blatant act on the part of Vladimir Putin and one that must be unacceptable to the world community. It cannot stand," McCain told the annual policy conference of the American Israel Public Affairs Committee.
Kiev has accused Russia of reinforcing its existing troops in the Crimea and asserting de facto control over Ukrainian territory.
Putin then received a swift legislative green light to send Russia`s military into Ukraine.
McCain insisted US forces should not be used to change the state of play in the region, where tensions have quickly soared to the top of the global agenda.
"I have to be very honest with you, there is not a military option that could be exercised now," McCain added.
"But the most powerful and biggest and strongest nation in the world should have plenty of options," ranging from economic sanctions to identifying and punishing kleptocrats and corrupt Russian officials by adding them to the so-called Magnitsky list, created through a congressional initiative in December 2012 and named after Russian lawyer Sergei Magnitsky.
The law barred Russian figures implicated in the 2009 prison death of Magnitsky, who had revealed embezzlement by Russian officials, from entering the United States, and it froze their US assets.
McCain, a leading congressional voice on defence, was the Republican presidential nominee in 2008, losing the White House race to Obama.
He heaped criticism on the President`s handling of the crisis and "a feckless foreign policy where nobody believes in American strength anymore."
"The President of the United States believes that the Cold War is over," McCain said.
"That`s fine, it is over -- but Putin doesn`t believe it`s over," he said.