Ever wonder how Washington manages to spend so much of our money so inefficiently? Here’s how: A new warplane, the F-35 Joint Strike Fighter, is being developed for the U.S. armed forces. It was supposed to have been ready for use by 2013. The initial estimate of the cost of developing and building 2,400 F-35s just a few years ago was $209 billion. By a few weeks ago, the cost estimate had rocketed to $300 billion. Don’t expect delivery of the jets until 2015, Air Force Secretary Michael Donley told members of Congress. And oh, by the way, the F-35 project cost probably will be significantly higher than current estimates, Donley added. How did this happen? The two-year delay occurred after the Defense Department uncovered problems with the F-35 contract. Last month, Defense Secretary Robert Gates announced $614 million in “performance bonuses” will be withheld from the lead contractor, Lockheed Martin Corp. Gates also said $2.8 billion will have to be added to the development cost.