A top Republican senator hammered President Trump on Sunday for not “pushing back” against Russian leader Vladimir Putin following global outrage over Moscow’s involvement in the nerve-agent poisoning of a former spy in Britain.

“The problem is that Russia is running wild, whatever we are doing is not working and the president for some reason has a hard time pushing back against Putin,” Sen. Lindsey Graham said on “Fox News Sunday.”

Britain blamed Russia for orchestrating an attack on ex-Russian spy Sergei Skripal and his daughter, Yulia, in Salisbury, England, on March 4.

In retaliation, Britain, the United States and their allies expelled more than 150 Russian diplomats from their countries.

But the South Carolina lawmaker said relations between the US and Russia resemble the Cold War years and he suggested Trump take a page out of President Ronald Reagan’s playbook on how to handle the Kremlin.

“This is the ’80s to me all over. I can tell you what Ronald Reagan did. Every time the Russians tried to advance their military technology, we one-upped them.

“Every time the Russians started running wild throughout the world, Reagan pushed back,” Graham said. “If I were Trump, I’d look at the Reagan playbook and economically isolate Russia.”

Graham said Trump needs to hit Putin where it hurts the most — the oil and gas industry that drives Russia’s economy.

“I would study every recipient of Russian oil and gas and see if we could find ways to supply those countries with oil and gas from a source outside of Russia,” Graham said.

While his administration has taken action against the diplomats, Trump himself has been quiet about personally calling out the Russia leader, writing on Twitter last month that “Getting along with Russia (and others) is a good thing, not a bad thing. ”

Trump’s tweet came after he was criticized for congratulating Putin on his election victory but did not mention the British nerve-agent attack or Russian meddling in the 2016 US election.

Trump and members of his administration and campaign are being investigated by special counsel Robert Mueller to determine if they colluded with Russia during the election.

Russia has called allegations that it was involved in the poisoning of the Skripals “nonsense” and has suggested that the Americans or British were behind the attack.

In retaliation, Russia has ousted 60 diplomats from the US Consulate in St. Petersburg.