Yesterday, Claire McCaskill voted to oppose  a compromise bill to authorize Federal Aviation Agency (FAA) spending. She, along with 20 other Senators, voted against weakening a National Mediation Board ruling allowing airline and railroad employees to form a union by a simple majority of those voting. The compromise would, as DailyKos Labor‘s Laura Clawson describes it, permit employers to:

… control information about what workers should be eligible to vote in an election, allowing them to pad the numbers required for the 50 percent of workers now required to even hold an election. Then employers would be able to delay the election, find out which workers were supporting the union and intimidate them. Not only that, but in cases where a larger non-union airline and a smaller union airline merged, the union and the contract would just be gone.

GOP efforts to gut union protections have held up a long-term FAA authorization for five years, and the compromise was negotiated by the Senate Democratic leadership. Add these considerations to the fact that there were lots of good things in the bill – it will facilitate the transition from radar to GPS flight control, for instance – and it becomes clear that remaining steadfast in support of the unions represents a reasonably tough-minded stance for a politician who has reliably wavered on most progressive issues.

Last week, McCasill scored when she stood up for reproductive rights and signed a letter protesting the Komen Foundation’s politically motivated treatment of Planned Parenthood. This week, by standing up for the right of unions to organize, she scored big for a second time. Who knows, maybe acting like a progressive will become a new habit for Senator McCasill – and if not, it’s good to know that there at least two issues on which we can count on her support.