President Obama and Democrats have been at great pains to insist they knew nothing about IRS targeting of conservative 501(c)(4) nonprofits before the 2012 election. They've been at even greater pains this week to ensure that the same conservative groups are silenced in the 2014 midterms.

That's the big, dirty secret of the omnibus negotiations. As one of the only bills destined to pass this year, the omnibus was—behind the scenes—a flurry of horse trading. One of the biggest fights was over GOP efforts to include language...