Well technically it wasn't seized, it was lost in war. But as far as I am concerned, Mexico can have most of it back. Especially California, which is pretty much already back in Mexico's hands anyway.
IT WAS SEIZED BY FUTURE CONFEDERATE SOLDIERS SUCH AS ROBERT E. LEE, JAMES LONGSTREET, "STONEWALL" JACKSON, P.G.T. BEAUREGARD, BRAXTON BRAGG AND OTHERS. THIS TERRITORY WAS TAKEN FROM MEXICO IN 1848 AND BECAME PART OF THE UNITED STATES. IT IS PART OF THEIR LEGACY. WANT TO GIVE IT BACK?