There were several reports this month about the Affordable Care Act, most of them positive: Participation is up; the so-called risk corridors, which critics call a giveaway to insurance companies, will make the government money; and the law will increase labor demand.

But more attention has been lavished on the negative: Over a decade, the equivalent of 2.5 million workers will drop out of the labor force because there are alternative health-insurance options, and the employment mandate was postponed again.

Separately, the drumbeat continued around Chris Christie. The Republican governor of New Jersey held a marathon news conference more than five weeks ago as he fired top aides whom he blamed for causing huge traffic disruptions on the George Washington Bridge last autumn. Christie insisted he knew nothing about the closures, which allegedly were political retaliation against Democrats.

Few new facts emerged about the initial controversy. But there has been a rash of other allegations, some stretching back to the 51-year-old governor’s high school days.

These two story lines ― one involving Democrats, the other about Republicans ― share common elements; they entail significant political fallout. Obamacare, even as the results get better, will hurt Democrats, perhaps seriously, in this year’s congressional elections. And a blow has been delivered to the presidential aspirations of Christie, who just three months ago was virtually coronated by Time magazine as the Republicans’ great hope for 2016.

Both demonstrate that once a narrative is established in U.S. politics, it’s very hard to shake.

The proliferation and growing influence of social media can accelerate a news narrative, like these two stories, says Teddy Goff, who directed President Barack Obama’s digital strategy in 2012. Over time, however, social media also may help a countertheme prevail, he says. This has little to do with overhyped chatter about media bias. There are effective offsets to media partisanship: the Internet versus talk radio; Fox News versus MSNBC. The mainstream media’s only discernibly consistent bias is on cultural issues ― abortion, gay rights, guns, race ― while a smaller-movement conservative news media, oblivious to balanced or fair journalism, effectively pounds messages that often end up in the mainstream media.

That message pounding, coupled with the Obama administration’s miscues ― the White House still resists tapping a chief executive officer to run the health-care initiative ― has locked in, for now, a negative view of Obamacare. This despite some good news: More than 10 million Americans have new or better health-insurance coverage than before; health-care costs are moderating; and reforms such as prohibiting discrimination against people with pre-existing conditions are kicking in.

Optimists such as Tom Daschle, the former Senate Democratic leader, think that once the kinks are worked out, Obamacare will become popular, much as Medicare and the prescription drug plan for seniors did. Still, as he acknowledges, “It’s taking a long time for people to understand” that the benefits outweigh the problems. Democrats running in November don’t have a long time.

Neither does Christie. Even if no new evidence emerges to contradict his proclamations of innocence, the damage may be irreversible. The governor’s appeal as a front-runner was that he could beat Hillary Clinton; his base is big-money Wall Street guys. As he gets hammered daily and now trails Clinton in presidential trial heats, the rationale and the base are eroding. He can’t shake the narrative.

It’s so embedded now that the best scenario for Christie is that he convinces voters that he had a bunch of second-rate top aides who engaged in political thuggery and that he had no clue what was going on. That’s not a compelling narrative for a would-be president.

By Albert R. Hunt

Albert R. Hunt is a Bloomberg View columnist. ― Ed.

(Bloomberg)