san francisco/washington dozen democratic attorneys general thursday seek intervene defend key part obamacare healthcare law subsidy payments insurance company threat court case 16 attorneys general lead california attorney general xavier becerra new york attorney general eric schneiderman file motion intervene case pending u.s. court appeal district columbia circuit case date back obama administration file republican-led house representatives federal government effort cut subsidy payments insurers individual plan create affordable care act often call obamacare subsidies payments help cover out-of-pocket medical expense low-income americans stake high maryland 400,000 people depend affordable care act get normal healthcare sound alarm true live stake say maryland attorney general brian frosh sign file trump repeatedly threaten withhold payments insurers amount billion year refer bailout attorneys general cite court file trump word vow let obamacare explode part reason intervention trump make clear view decisions health insurance millions americans little political bargain chip court file say situation extremely urgent democratic officials argue state insurance regulators make critical choices shape insurance market next year several insurers include aetna aet.n humana hum.n largely leave obamacare exchange cite pool patients sick expect therefore expensive insurers also repeatedly call trump administration fund cost-sharing subsidies attorneys general proponents obamacare say threats withhold payments already wreak havoc marketplaces part reason healthcare consumers see double-digit rate increase democratic attorneys general emerge significant opponents trump administration take lead role successfully block trump executive order restrict travel muslim-majority countries also resist efforts roll back environmental regulations attorney general kentucky deeply conservative state among democrats join court file even state republican governor pledge rollback medicaid expansion make possible obamacare may 2016 u.s. judge rule favor republicans subsidies case find obama administration need explicit congressional approval obama administration appeal trump take office leave new administration ponder proceed appeal court put litigation hold november presidential election request republican house lawmakers motion intervene may grant court february court reject similar motion file democratic attorneys general seek help defend consumer financial protection bureau legal battle could defang agency litigation could become moot congress pass new healthcare legislation replace obamacare house pass bill call american health care act early month senate recently begin write version bill warn could take months pass trump administration take action past several months undercut obamacare regulatory authority back enforce individual mandate require everyone purchase health insurance else pay penalty tighten enrollment obamacare market enable people sign insurance plan outside healthcare.gov flagship site obamacare obama administration heavily advertise democratic attorneys general seek intervene obamacare case