South Carolina Republican Sen. Lindsey Graham said in a tweet on Monday that he will take Sen. John McCain's seat if he doesn't return from war-stricken Syria.
McCain, a Republican senator from Arizona, on Monday visited Syria in an unannounced and surprise event given the ongoing civil war, NBC News reported. He is one of Congress' strongest advocates for increasing America's role in Syria.
He crossed the Turkey-Syria border with Gen. Salem Idris, the leader of the Supreme Military Council of the Free Syrian Army.
Both Graham and McCain are members of the "Gang of Eight," a group of Democratic and Republican senators who presented President Obama with a bipartisan agreement on immigration reform last month.