According to Politico, GOP Senator Lindsey Graham has some advice for Joe Biden.<br />Graham thinks Biden needs to "up his game" after underperforming at last week's Democratic presidential debate.<br />Graham says other candidates shouldn't underestimate him in the crowded presidential primary race.<br />Graham "Face the Nation" taped Saturday. "Underestimate Joe Biden at your own peril."<br />Graham served alongside Biden in the Senate. <br />
