Fun congressional procedure

On Matt's question about the Iraq spending bill and defunding the troops: As I understand it, on appropriations matters if the president vetoes a budget Congress usually passes a continuing resolution that allows government services (in this case the Department of Defense, I suppose) to operate until a new version of the spending bill is passed or the continuing resolution expires. This isn't required, but is incredibly common. And is a de facto way for the president (or the Congress) to avoid charges of abandoning troops in the field.