If Republicans want to lose Congress, there s one surefire way: let Americans know that they will be in for at least two more years of gridlock and obstruction if they win. John McCain, in a stunning admission, promised exactly that.In a radio interview on Philadelphia s 1210 WPHT radio on Monday, McCain wasn t able to say with certainty that Donald Trump would be better at nominating Supreme Court justices than Hillary Clinton would be, but he does promise that if Clinton wins, there s no way the Senate will ever vote on one of her Supreme Court nominees.Later in the interview, McCain used the opportunity to make the case for fellow Republican Sen. Pat Toomey, who is locked in a close battle to retain his Senate seat in Pennsylvania. McCain promised that Republicans would be  united against any Supreme Court nominee  put forth by Clinton. I promise you that we will be united against any Supreme Court nominee that Hillary Clinton, if she were president, would put up,  McCain said.  I promise you. This is where we need the majority and Pat Toomey is probably as articulate and effective on the floor of the Senate as anyone I have encountered. Source: CNNHere s the audio:Voters won t buy it. While McCain s seat is pretty safe, the Senate as a whole is not. Republicans have to win at least 21 seats to retain their majority in the Senate. Democrats only need 15. It s not just that, either. Voters know that it s Congress, not President Obama, who is responsible for the gridlock in Washington, and they are sick of it. Most Americans want the Senate to give Obama s Supreme Court nominee, Merrick Garland, a hearing and ultimately, an up or down vote. Instead, McCain and Republicans are promising more of the same, which is absolutely nothing. Trust me, Americans will punish them at the polls, especially as Donald Trump s campaign continues its downward spiral.Featured image via Win McNamee/Getty Images.