WASHINGTON — As tensions and turmoil escalate in Ukraine, America’s response to the crisis is becoming an increasingly contentious issue in Washington.

Deadly clashes in Odessa point to a grim reality: with every passing day, Ukraine teeters closer to civil war between a pro-Western government in Kyiv and pro-Russian militias backed by Moscow.

A new round of U.S. sanctions targeting Russian President Vladimir Putin’s inner circle has not altered Moscow’s aggressive posture toward Ukraine, a fact noted by President Barack Obama’s critics in Washington.

“President Obama talks tough about Vladimir Putin. But his actions have not gone far enough to change Putin’s calculation that the benefits of his aggression outweigh the costs,” said Republican Senator Marco Rubio.

Last week, Senate Republicans introduced a bill that would subject Russian banks and other key economic sectors to U.S. penalties.

“Our economic well-being is deeply dependent on our national security. The problem is that President Obama does not seem to understand this. Instead of shaping world events, he has often simply reacted to them,” Rubio said.

However, Obama is not ruling out elements of the Republican proposal.

“If Russia continues on its current course, we have a range of tools at our disposal, including sanctions that would target certain sectors of the Russian economy,” the president said.

But in a news conference with German Chancellor Angela Merkel, Obama said he hopes diplomacy will make further sanctions unnecessary.

“Our hope is that we should not have to use them. We are not interested in punishing the Russian people. We do think that Mr. Putin and his leadership circle are taking bad decisions and unnecessary decisions and he needs to be dissuaded from his current course,” Obama said.

The crisis in Ukraine is but one source of friction in the foreign policy arena between the White House and its critics.

Many Republicans, and even some Democratic lawmakers, have urged a more robust U.S. response to the fighting in Syria, and are skeptical about the administration’s effort to limit Iran’s nuclear ambitions through diplomacy.

  aggression, nation, obama, president, Republicans, Russia, sanctions, Ukraine, united states