Last I checked $140k is about the going rate for government contractor software engineering work in the DC/Northern Virginia area. Add $10-20k for a Secret clearance or Public Trust and $30-50k for a Top Secret clearance (though you'll probably have to deal with working in a SCIF at least some of the time with a clearance). I'm pretty sure you can push that latter number even higher if you get a TS/SCI and start doing spooky stuff.