A District of Columbia federal judge rejected a lawsuit Wednesday that challenged tax credits for Obamacare coverage in the 36 states with federal-run exchanges – one of the most significant remaining legal fights over President Barack Obama’s health care law.The four individuals who brought the lawsuit, Halbig v. Sebelius, had argued that the IRS overstepped its legal authority by allowing federal-run exchanges to provide tax credits for people who purchase health insurance. They contended that the Affordable Care Act only allows for state-run exchanges to access such credits and that Congress purposefully designed the law that way to incentivize states...