Sen. Marco Rubio (R-Fla.) said Saturday that President Obama has not done enough to deter Russian President Vladimir Putin from invading Ukraine, calling for a tougher response from Washington.

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

The Florida lawmaker and potential 2016 presidential hopeful, said that Putin’s invasion of Ukraine is a “clear challenge” to the principles of a Democratic society. But he said he was disappointed by the weak response from the Obama administration.

President Obama was also criticized by Republicans for his handling of the civil war in Syria and, more recently, the nuclear crisis in Iran.

“The problem is that President Obama doesn’t seem to understand this,” Rubio said. “Instead of shaping world events, he has often simply reacted to them. And instead of a foreign policy based on strategy, his foreign policy is based on politics.”

Rubio called on Obama to support a Republican bill that would increase sanctions against Russia and provide Ukraine with military assistance.

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