If you can’t win by getting them to vote for your candidate, win by splitting the vote of your opponent : Seeking any advantage in their effort to retain control of Congress, Democrats are working behind the scenes in a number of tight races to bolster long-shot third-party candidates who have platforms at odds with the Democratic agenda but hold the promise of siphoning Republican votes. The efforts are taking place across the country with varying degrees of stealth. And in many cases, they seem to hold as much risk as potential reward for Democrats, prompting accusations of hypocrisy and dirty tricks from Republicans and the third-party movements that are on the receiving end of the unlikely, and sometimes unwelcome, support. In California, Republicans have received recorded phone calls from a professed but unidentified “registered Republican” who says she is voting for the American Independent Party’s candidate for a House seat, Bill Lussenheide, not for the incumbent Republican, Mary Bono Mack. The caller says she is voting that way because “it’s time we show Washington what a true conservative looks like.” The recording was openly paid for by the Democratic candidate for the seat, Mayor Steve Pougnet of Palm Springs. In Pennsylvania, the Democratic candidate for a suburban Philadelphia House seat, Bryan Lentz, admitted this week that his volunteers helped Jim Schneller — a prominent skeptic of President Obama’s citizenship — collect petitions to run against Mr. Lentz and his Republican opponent, Pat Meehan. In Nevada, conservative radio listeners have heard an advertisement promoting the Senate campaign of a “Tea Party of Nevada” candidate, Scott Ashjian. The ads criticize Sharron Angle, the Republican nominee and favored candidate of the actual Tea Party movement in the race against Senator Harry Reid, the Democratic majority leader. Pathetic.