The failed effort by Democrats to recall Wisconsin Gov. Scott Walker prompted much speculation about the tenuous future of American unions, but the real future of American labor is being determined right now not in a high-profile electoral fight but in an obscure legal battle in Texas. Everyone on both sides of the fight recognizes that either unions will win the right to represent more private-sector workers or else will wither and die. That’s why the Communications Workers of America’s effort to organize about 10,000 passenger service agents at American Airlines is so important. Labor relations in the airline industry are governed by the Railway Labor Act rather than the generic labor-law framework that covers most of the economy. Under longstanding RLA rules, if 35 percent of workers in an unrepresented “craft or class” signed a card indicating a desire for union membership, that triggered an election.

A union attempting to organize such a workplace still needs to win the election, and the 35 percent bar is slightly higher than the 30 percent one that prevails in most other circumstances, but the RLA gives unions more latitude in terms of permitted strike tactics once they are organized.* The CWA made considerable headway in trying to organize Americans’ customer service agents. American Airlines management, like most of corporate America, takes a dim view of labor unions and was not excited about this development. For starters, American Airlines was already in financial trouble and, indeed, filed for bankruptcy last November in hopes of wriggling out of obligations to its existing unionized workers. The bankruptcy process itself, however, has generated considerable pressure from some creditors—and also from American’s unions—for the airline to agree to a merger with US Airways. From a management perspective, this would be an unappealing outcome: With American bankrupt, it would amount to a US Airways takeover and lead to job losses among American executives.

Fortunately, congressional Republicans were happy to help American against its unions. Last summer the GOP forced a multifront standoff with Democrats over funding the Federal Aviation Administration. This forced some temporary furloughs of FAA workers, threatened to paralyze the country’s passenger aviation system, and briefly focused on a highly partisan effort to kill pork-barrel subsidies to rural airports with the specific de-porked communities suspiciously targeted at states with Democratic senators. Ultimately the issue was resolved by Republicans agreeing to fund the FAA and Democrats agreeing to amend the RLA to raise the card-check threshold to 50 percent of the workforce.

So far so good. But unfortunately for American, by the time that deal was sealed in February, the CWA had already obtained the 35 percent it needed to move ahead with an election among American Airlines passenger service agents. And so the National Mediation Board decreed that an election would take place, starting June 21 and continuing through August 2.

Then late on Friday afternoon, along came Judge Terry Means of the U.S. District Court for the Northern District of Texas with an injunction halting the election. In his view, the new 50 percent standard should be applied retroactively to the workers’ petitioning for union representation, and American would suffer “irreparable injury” from allowing the vote to go forward.

On the legal merits, this is one of these cases where it’s difficult to tell the difference between law and politics. Asking what Congress intended to happen in this case is essentially meaningless. The legislation was the outcome of a high-stakes standoff between two political parties with fundamentally different opinions about what they wanted to see happen. But the Democrats who wrote the legislation on the Senate side clearly sided with the union in a May 15 letter (PDF) noting that not only would it be unusual to retroactively apply legislation without specific language to that effect, but that in floor statements senators specifically abjured that interpretation of the statute.

As a policy matter, the whole story illustrates how fundamentally bleak the outlook for American unions is. Political polarization has given Republicans a clear-cut partisan interest in doing whatever they can to block unionization efforts, completely apart from questions of ideology and business interests. And the basic tactic of changing rules midstream and applying them retroactively can be used in an endless number of permutations to block major organizing efforts. The CWA and the organizing workers will, of course, appeal the decision. But the conservative majority on the Supreme Court proved last week that it’s no more sympathetic to the union cause than the rest of the American right. The result is a set of political and legal situations in which it’s difficult to see how any major private-sector organizing battle can be won unless the Democratic Party has a sudden change of heart and starts fighting equally aggressively on the other side of these issues.

Correction, June 26, 2012: This article originally stated that the 35 percent threshold required by the Railway Labor Act was lower than the normally prevailing one when in fact it’s higher. (Return to the corrected sentence.)