The letter estimates that $1.8 trillion in planned spending over the next 10 years would be cut if the wars were ended by the start of fiscal year 2013. It added that, to date, they have cost "at least $2.3 trillion, with an additional $884 billion in future costs for veterans and their families."

"Exorbitant spending on failed wars that have killed thousands of Americans must not be exempt from budgetary scrutiny," the letter adds. "Before we ask American families to pitch in more, let’s bring our troops home — and, in the process, our tax dollars home.

The letter is being led by Rep. Lynn Woolsey (D-Calif.). As of noon Thursday, it had 32 co-sponsors — all Democrats, except for Rep. Walter Jones (R-N.C.).