Sen. Lindsey Graham’s vowed to be “President Trump’s worst nightmare” if the situation in Syria doesn’t turn around.

The South Carolina Republican claimed in an interview with CBN News that Trump needs to “up his game” in defense of Kurdish soldiers who fought alongside Americans against ISIS.

“I am looking to President Trump to change this. I will do anything I can to help him, but I will also become President Trump’s worst nightmare. I will not sit along the sidelines and watch a good ally, the Kurds, be slaughtered by Turkey and watch Iran move into Syria and become another nightmare for Israel. This is a defining moment for President Trump,” said Graham, adding, “He needs to up his game.”

[Related: Lindsey Graham feuds with Trump over Syria: 'I will not be quiet.']

Graham claimed Trump’s inaction in Syria could cost him the 2020 presidential election.

“If you remove all of our forces from Syria, you’re throwing the Kurds over. ISIS will come back on your watch and Iran will take over and you, my friend, will be in great jeopardy of losing an election we can’t afford you to lose,” said Graham. ”So don’t be like Obama, be like Reagan stand up to Erdoğan.”

Graham has been a vocal critic of Trump’s decision to withdraw U.S. troops from northeastern Syria. That region was home to the Kurds and thousands of ISIS prisoners. Since the decision, Turkey has invaded the region and many ISIS prisoners have escaped.

During a press conference on Wednesday, Trump brushed off other criticisms from Graham, saying, “Lindsey Graham would like to stay in the Middle East for the next thousand years.”

Although Graham has little control over U.S. troops, he announced that he would be hitting Erdoğan with “sanctions from hell.”

“I’m going to break this thug’s back,” Graham promised.