Hopes for an extension of health care subsidies were diminishing in Congress this week as Republicans and Democrats largely abandoned the idea of bipartisan talks on the issue, increasing the odds that millions of Americans could see sharp premium spikes starting Jan. 1. Democrats who agreed earlier this month to reopen the government in exchange for a December health care vote were hoping they could work with Republicans to extend the COVID-era Affordable Care Act tax credits that help many Americans pay for their health coverage. “I don’t think at this point we have a clear path forward, I don’t think the Democrats have a clear path forward,” Senate Majority Leader John Thune said Tuesday after Republicans met and discussed different proposals to overhaul the law.