Democrats and Republicans seem to be at an impasse over whether and how to extend enhanced premium subsidies for health insurance bought on the Affordable Care Act marketplace, as a key enrollment deadline to secure coverage fast approaches. Policy experts say affordability is at the epicenter of that fight.

The political squabbling appears to be a sort of "proxy debate" over the high and rising costs of health insurance and health care in the U.S., said John Graves, a professor of health policy and medicine at Vanderbilt University.

"The beating heart of this debate is, where are we as a country in terms of how we should help people afford their health insurance?" Graves said.

Senate fails to advance health legislation

Two dueling health measures failed in the Senate on Thursd

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