The Justice Department has filed its brief on the question of whether it is constitutional to compel Americans to obtain minimum health insurance, its first legal document explaining the federal government's case supporting the health reform law in preparation for arguments before the Supreme Court in March. The 130-page brief filed Jan. 6 adheres to arguments it used in lower courts to support the individual mandate, one of four legal questions that attorneys will argue before the Supreme Court. Justice will file briefs on the other three legal questions over the next month.