Civil War: House of M #4

Genosha has been invaded by agents of the U.S. and Magneto dispatches two of them before he discovers that Winter Soldier has fatally wounded Xavier. After Charles dies in his arms, Magneto decapitates Bucky with his own shield. Not willing to allow the U.S. attack to slide by, Magneto hurls Captain America’s bloody shield into the Oval Office and begins a final battle on the White House lawn. Trask sends ceramic Sentinels against the mutants and launches nukes on Genosha.