WEST PALM BEACH, Fla. (AP) — Rep. Patrick Murphy had been a cautious defender of President Barack Obama's health care law for much of the last year, telling constituents in his swing-voting district that the far-from-perfect measure is critical to helping cover uninsured Americans.

Then the new health care law made its disastrous debut. The federal health care website repeatedly crashed, blocking millions from browsing insurance plans. Questions about its security mounted. And cancellation notices hit people who buy their own plans, undercutting the president's vow that those who liked their coverage could keep it.

Now the South Florida lawmaker — one of nine Democrats representing districts Republican Mitt Romney won in 2012 — is distancing himself from the administration and heeding GOP calls to delay key parts of the health care law, illustrating the Democratic Party's challenge as it fights to keep control of the Senate and retake the House next year.