A federal judge in Michigan ruled Thursday that the new health-care overhaul law is constitutional, rejecting an argument that Congress lacked the power to require the legislation's "individual mandate," which orders virtually all Americans to purchase health insurance.

Other federal courts have already dismissed some challenges to the law on technical grounds - ruling, for instance, that the plaintiffs lacked standing. However, the decision issued Thursday by Judge George Caram Steeh of the Eastern District of Michigan is the first to reject a claim based on the merits, marking a notable victory for the Obama administration.