Growing numbers of Americans are signing up for insurance through President Obama's health law, with more than 250,000 selecting a plan in November, according to a new government report. That is more than double the number in October, when problems with the new HealthCare.gov website made enrollment virtually impossible in most states for long stretches of time. Last month's tally is fueling renewed optimism among supporters of the Affordable Care Act who believe that fixes to the federal site will rescue the law, commonly known as Obamacare, from its disastrous debut.