Sen. Lindsey Graham, R-S.C., told Fox News' KT McFarland that Russian President Vladimir Putin must "pay a heavy price for annexing Crimea in violation of every international norm."
"I would not move on and try to de-escalate ... I would sanction [Putin's] economy, I would sign into law the Senate- and House-passed sanctions on the Russian energy sector," Graham said. "I would not be sitting down and talking to him."
Graham suggests boosting U.S. energy exports to Europe as a way to counteract their dependence on Russian resources.
He said the White House is letting Putin's recent actions go unanswered. "[Obama] told Putin don't go into Crimea, you'll pay a price -- he went into Crimea and I don't see any price being paid."
Graham, who serves on the Senate Armed Services Committee, said he isn't concerned about Putin attacking a NATO member near Russia's border -- but instead, "that [Putin] is going to suck Obama into negotiations where Obama [legitimizes] his taking of Crimea."
Critics have warned any negotiations with Russia without Ukraine's involvement could hurt Kiev's push towards reform.
"I see a scenario where Putin gets Crimea with legitimization and that through diplomacy he is able to convince us to go to the Ukrainian people and abandon your hopes for democracy ... and knock off wanting to be a part of the European Union," Graham said.
Watch the full interview above.