The National Federation of Independent Business, representing the interests of small businesses across America, today joined more 20 states on the lawsuit challenging the constitutionality of Obamacare. The move is the latest blow to President Obama’s post-passage public relations effort.

NFIB’s involvement was prompted by the individual and employer mandates, new taxes and onerous paperwork requirements. An accompanying statement said the Patient Protection and Affordable Care Act would devastate small business, threatening their viability. The lawsuit’s two main legal claims involve the unconstitutionality of the individual mandate.

Last month Heritage’s John Ligon documented how Obamacare penalizes small businesses: higher health care costs, an ineffective small business tax credit, higher regulation compliance costs, and Medicare taxes on “flow-through” and investment income.

NFIB chief executive Dan Danner said the law simply went too far:

We want to make it very clear: NFIB has a long history of working on and supporting healthcare reform. We are not part of the ‘Just say no’ crowd. Small businesses DO need reforms that help to reduce costs and increase choices. We have encouraged reforms that cover pre-existing conditions, help to create effective and affordable national exchanges, provide the ability to buy across state lines, and include liability reform. But this new law resulted in more bad than good for our nation’s job creators. And this law is a bridge too far in terms of the future of our constitutional freedoms and liberties.

So what makes the NFIB’s involvement important? The fact that small firms represent 99.7 percent of all employers, according to the U.S. Small Business Administration, sends a strong message Obama.