If you think air travel is bad now, just wait until the airport screeners unionize.

It's about to happen. The Obama administration just decided that the Transportation Security Administration will vote on unionizing next year. TSA Administrator John Pistole is widely expected to grant this union collective bargaining rights.

This will not improve holiday travel. Unions already make getting rid of problem employees difficult. Those screeners who pat down too enthusiastically will get a union to hide behind. Do you think that will improve travel? Americans put up with these screenings to protect against terrorists.

Unfortunately, unionizing will also reduce security. Consider what happened four years ago, when unionized airport screeners in Toronto protested their contract by hand-inspecting every piece of luggage. Lines of passengers waiting to get to their flights piled up over Thanksgiving. Toronto authorities eventually rushed 250,000 passengers onto their flights-without searching them. Fortunately, none of those passengers were terrorists. But as one Canadian security expert wryly noted, "If terrorists had known ... that their baggage wasn't going to be searched, that would have been bad."

Unions will reduce safety even without labor disputes. Collective bargaining requires the government to negotiate before changing working conditions. However, terrorists are not going to wait until bargaining ends to attack. Unions reduce the flexibility the government needs to respond to threats.

That is why the founders of the modern labor movement thought that unions belonged only in the private sector. They wanted unions to win workers a greater share of business profits. But the government earns no profits. Government unions organize against voters and taxpayers-something they thought made no sense. Even Franklin Roosevelt, America's most pro-union president, opposed unionizing government. He considered unions obstructing public services intolerable.

The government eventually allowed some federal employees to unionize.

But Congress decided that the government needed maximum flexibility to protect national security. Employees of the CIA, the FBI, and the Secret Service do not collectively bargain with Uncle Sam. Nonetheless Obama appointees have decided that airport security screeners should. Why would the president do this? Political pressure. Unions are one of the most well-funded special interests in the country.

They collect dues from millions of workers and spend that money politicking. Unions ran half of the 20 largest Political Action Committees in the last election. One of their top political priorities is organizing more government employees. Private-sector union membership has been dwindling for decades. Unionized companies such as General Motors have lost ground to Honda and other more flexible non-union competitors. The government, however, has no competitors. Unionized government employees do not lose their jobs if they perform poorly. So public sector union ranks have expanded over the past generation.

Last year those paths crossed: a majority of union members now work in the government. The 21st century union movement consists largely of government employees.

Unionizing the TSA would add 50,000 dues-paying members to union ranks - as many as currently work for GM. Those workers would pay tens of millions in annual dues. Union leadership dearly wants this plum prize. Unions spent half a billion to elect the president. They spent more on the mid-term elections than the Chamber of Commerce did. So when they speak, Obama listens. Remember that when you're waiting in line for your holiday pat-down next Thanksgiving.