Washington (CNN) Republican Sen. Lindsey Graham is stuck once again between a President whose support he needs to win re-election and his lifelong friendship with the late Arizona Sen. John McCain, who encouraged all to put country first.

But time and political necessity have softened Graham's public grievances with President Donald Trump. The presidential embrace has been months in the making. Beginning with golf outings with Trump, Graham now frequently takes calls from the President.

In recent months, the South Carolinian has become a close Trump confidant on Capitol Hill, an alliance that has afforded him broad influence over the GOP conference and the White House, but at times tested his ability to defend his friend McCain from Trump's harsh attacks.

During Supreme Court Judge Brett Kavanaugh's contentious confirmation battle, Graham snapped at his Democratic colleagues for what he said was the biggest "unethical sham since I've been in politics," a moment that was largely seen as a public opportunity to side with Trump in a battle that had divided Republicans behind the scenes.

Over the weekend, Trump tweeted his latest gripe against McCain, who died in August, referring to the controversial dossier that has become one of Trump's longest-held grudges against the former Arizona senator.

Read More