One of the policies that President Obama often cites to defend his health care law is the mandate forcing insurers to allow “children” to stay on their parents’ policies until age 26. That’s understandable, because the idea is among the most popular individual provisions in the otherwise unpopular law. A New York Times/CBS poll released in March found 67 percent of Americans want at least the health care law’s individual mandate overturned by the U.S. Supreme Court, but 68 percent supported the mandate for those under 26.

For this reason, many Republicans have been reluctant to criticize this aspect of Obamacare. The Wall Street Journal last month reported Republican Rep. Steve Stivers, of Ohio, was even floating the idea of increasing the mandate to age 31. But a new report from Republicans on the Congressional Joint Economic Committee, or JEC, details why this aspect of Obamacare, often referred to as the “slacker mandate,” is a disastrous policy.