Scoop: Shaheen to highlight health care costs with "shadow hearing"

• They are also previewing the arguments they will be using against Republicans in next year's midterms.

Driving the news: Shaheen, who has been pressing Republicans to cut a deal on the Affordable Care Act subsidies, will hold an afternoon hearing titled "The Clock Is Ticking: Why Congress Must Extend the Enhanced Premium Tax Credits."

• In public and private, Shaheen has been pressing her Democratic colleagues to focus their messaging on the shutdown as a fight to lower health care costs for Americans.
• She'll be joined by a dozen Democratic senators and four witnesses to discuss how some Americans will see their health insurance costs increase if Congress doesn't continue the subsidies.

Zoom out: Some GOP senators are open to extending the enhanced tax credits in the insurance exchanges — if certain changes are made to the program.

• But GOP leaders insist they won't consider a broader deal that would trade Democratic support to help fund the government in exchange for GOP votes on health care subsidies until later this year.

• "We can have that conversation. But before we do, release the hostage. Set the American people free. Keep the government open," Senate Majority Leader John Thune (R-S.D.) said.

Yes, but: Republicans are balking at the price tag for extending the subsidies, which are estimated to cost $335 billion over 10 years.

• Some GOP senators also argue the current formula for the tax credits — which allow individuals to access the subsidies up to 400% of the poverty level — is too generous.