Oh, how the mighty have not fallen.

Sheldon Silver, the powerful former speaker of the New York State Assembly, survived his corruption prosecution in July. That’s when an appeals court overturned his bribery conviction.

The next to slip away was William J. Jefferson, a onetime Democratic congressman from Louisiana. The bulk of his conviction — which occurred after he was caught with $90,000 in his freezer — was tossed out in October.

Then, on Thursday prosecutors who specialize in graft suffered what amounted to a double disappointment: within hours of each other, two different juries declared that they were deadlocked in the high-profile corruption trials of Robert Menendez, a Democratic senator from New Jersey, and Norman Seabrook, the longtime leader of the corrections officers’ union in New York.

It would seem that the government is having trouble indicting public figures and making the charges stick. But however demoralizing this recent string of losses may have been for prosecutors and law enforcement agents, it cannot be solely blamed on them.