Key parts of the new healthcare law will go into effect on Jan. 1, just before a Republican-controlled House returns to Washington. The massive overhaul of healthcare approved by Congress earlier this year will begin to take effect in 2011, though some of the biggest changes prompted by the law - including the mandate that everyone buy insurance, the state insurance exchanges and subsidies to help most Americans buy insurance - don't kick in until 2014. Still, more than 20 provisions of the reform law go into effect in 2011, according to a Kaiser Family Foundation timeline. Republicans under Speaker-designate John Boehner (Ohio) are expected to try to withhold funding for the new law, which could impede its implementations. Democrats, however, will fight any efforts at defunding the law aggressively.