Graham: I'm seeking to make Trump successful 'but not at all costs'

Sen. Lindsey Graham (R-S.C.) says he chose to be "reflective" after losing to President Trump in the 2016 Republican primary race.

The longtime Senator appears in a promo video for the next episode of "Axios on HBO."

"[Hillary Clinton] was secretary of State, first lady, United States senator. She lost to Donald Trump," Graham tells Axios in the promo."

"I lost to Donald Trump," he added.

Graham also tells the news outlet that he chose "to try to find out how to make Trump successful but not at all costs."

Throughout Trump's presidency, Graham has been one of the president's staunchest supporters.

However, Graham - a known defense hawk - was one of Trump's loudest critics after the president decided to remove U.S. troops from the northeastern border of Syria last week.

At the time, Graham said the policy move could end up being the biggest mistake of Trump's presidency if it isn't reversed.

Similarly, the senator, a member of the Senate Foreign Relations Committee, showed apprehension over the Turkish cease-fire that was facilitated by Vice President Pence and Secretary of State Mike Pompeo earlier this week. 

General Mazloum Abdi, the commander of the Syrian Democratic Forces, "is concerned about the cease-fire holding and was emphatic that he will never agree to the ethnic cleansing of Kurds that is being proposed in Ankara," Graham tweeted.

"A buffer zone is acceptable to the Kurds but a military occupation that displaces hundreds of thousands is not a safe zone. It is ethnic cleansing," he added.

The cease-fire is supposed to last five days, during which Kurdish forces will vacate Turkish President Recep Tayyip Erdoğan's desired "safe zone."