The American Federation of Government Employees, which represents 500,000 federal employees. making it the largest union federal employee union, has sued the federal government, seeking more disclosure about which federal employees and positions will be declared non-essential in the event government shuts down at midnight Friday night.

The last time the government shut down during the 1995-1996 budget standoff, much of the drama came around the interruption of federal services.  This time, though, the heat will likely be felt over unionized federal workers.

There are now two million federal workers, almost half of whom are unionized, reflecting a national move toward the expansion of government unions.  This at a time of prolonged contraction in union membership in the private sector.  As we saw in Wisconsin, Indiana and Ohio, union workers who are firmly allied with liberal Democrats are pulling out all the stops to make it hard on Republicans who are pushing legislation to curb union power.

On Tuesday Barack Obama warned about the disruptions that would be caused by the temporarily furlough of hundreds of thousands of federal workers, but another side effect might be to have those workers marching on the Capitol to demand to have their checks restored.

If the government does close, look for federal unions to try to replicate the confrontational tactics which have played out in Madison, Wisconsin.

That could be bad news for Obama who would rather talk about disposed widows and orphans than the hardships of federal workers who are paid 20% more than private sector workers.