It’s time to tell your people to back off Obama campaign manager Jim Messina has a message for No Labels, which principal Joe Lieberman insisted would only run a candidate for president if they thought he or she could win. And just as important, Lieberman has been clear that they would not run anyone if it looks as though it would help Trump win: The idea that a “unity ticket” featuring a Republican and a Democrat could somehow produce a nominee with “a clear path to victory” is worse than a political fiction. The group behind it, No Labels, is pushing a dangerous lie that would simply serve to put Trump back in the White House. How can I be so certain? Look at the last half-century of election results. In modern U.S. presidential history, third parties have not won much. In 1968, George Wallace won 46 electoral votes by running a regionally-targeted (and racist) campaign. Since then, they’ve won zilch — not a single state. Not Gary Johnson or Jill Stein in 2016, and not Ralph Nader in 2000. None of them broke 5 percent of the vote. Then there’s Ross Perot, who No Labels aspires to emulate for his appeal to “the vast middle of the electorate.” Despite unlimited cash and facing an unpopular incumbent in George H.W. Bush and a near-unknown in Bill Clinton, Perot failed to win a single state. Can No Labels twist the data and make an argument that Perot could have won if he had done things differently? Sure!…