ObamaCare includes so many taxes that it's hard to keep track, but one of the worst takes effect on Jan. 1. This beaut is a levy on health insurance premiums that targets the small business and individual markets.

At $8 billion in 2014 and $101 billion over the next decade, the insurance tax is larger than ObamaCare's taxes on medical devices and prescription drugs combined. The Internal Revenue Service classifies the tax as a "fee" but it functions like an excise tax on premiums. The IRS collects an annual flat amount specified by theAffordable Care Act to be allocated among the insurers according to market share.

But not all markets. IRS regulations published in November excluded "any entity that is a self-insured employer to the extent that such employer self-insures its employees' health risks." Since about four of five employers with more than 500 workers and most union-negotiated health plans are self-insured, they are spared from the tax. So is insurance on behalf of "government entities," such as original Medicare (but not privately run Medicare Advantage).

This political selectivity means the most gold-plated public, private and labor plans are exempt and the tax burden falls on the saps who work for small businesses, the self-employed and individuals—i.e., the people who can least afford it.

The White House tells business that the tab will be picked up by deep-pocketed insurers, which is good for a laugh. The Congressional Budget Office reports the tax will be "largely passed through to consumers in the form of higher premiums" and "would ultimately raise insurance premiums by a corresponding amount." The Joint Tax Committee and private economists, such as former CBO director Doug Holtz-Eakin, say the tax will boost insurance costs about 2% to 2.5%. The consultant Oliver Wyman estimates the take will rise to as much as $500 per covered worker by decade's end.

Wasn't the Affordable Care Act supposed to be about expanding coverage in part by lowering premiums, not slapping on more overhead? By this liberal logic taxing cigarettes should create more smokers.

Oh, and to salt the wound, this "fee" is not deductible for corporate income tax purposes. In other words, health plans pay the tax and then federal and state taxes on the taxed amount. Mr. Holtz-Eakin estimates this unusual taxes-on-taxes rule means that the effect on premiums is 54% larger than the dollar amount of the tax itself.

The research arm of the National Federation of Independent Business calculates that the higher insurance costs will shrink hiring by 146,000 to 262,000 jobs over the next decade, with 59% of those losses hitting small business. They'll also be further encouraged to dump coverage and send their workers to the mercies of the ObamaCare exchanges. The latter was probably a main liberal purpose from the start.

Louisiana Republican Charles Boustanyand Utah Democrat Jim Matheson's repeal bill already has 229 cosponsors, or a House majority, including some dozen Democrats. The White House naturally promises a veto. Happy New Year.