Health care is the GOP's greatest political vulnerability in midterm elections, and the Trump administration has poured gasoline on already burning fire.

The plan comes as single-payer insurance, an issue once confined to the fringes of the left, moves into the mainstream of the Democratic Party.

Tax bill debate update: The White House continues to signal openness to a tax overhaul that features a corporate rate higher than 20 percent. Polls show most Americans disapprove of tax plan. Offshore provisions stir trade concern.

Early opposition to the tax bill among the Senate GOP concerns tax treatment of partnerships and other pass-throughs, the repeal of the ACA individual mandate, and the deficit implications of the plan.

Senate GOP tax plan still grappling with adding a repeal of the ACA individual mandate, preserving the estate tax, taxing NQDC plans for high earning workers, and repealing state and local tax deductions.

President Donald Trump called Wednesday for repealing the Obamacare individual mandate in a tax overhaul, a day before House GOP leaders planned to unveil a bill without that provision.

Internal GOP strife and frustration led to the tax bill being delayed, according to a former House aide whos familiar with the deliberations.

Senator Tom Cotton has what he calls a "modest proposal" for the tax legislation that House Republicans are poised to release on Wednesday: eliminate the Obamacare individual mandate.