Falk, who received the endorsement of the Wisconsin AFL-CIO on Wednesday, released her first TV ad on Monday, a positive biographical spot. Early on, Barrett's running as a unity agent, trying to build an early coalition that includes liberals and moderate Democrats. But labor doesn't like him and contending with unions is going to be a difficult task in what's expected to be a close primary race. A key distinction between Falk and Barrett: Falk has vowed to veto any budget that does not restore the collective bargaining abilities Walker's budget repair bill stripped from public workers. Barrett is not promising a veto in advance. The primary is May 8.