Michael Tanner of the Cato Institute devotes his latest National Review Online column to an examination of the likely impact of the federal health care law.

In 1850, the French economist Frederic Bastiat wrote “That Which Is Seen and That Which Is Not Seen,” in which he noted that, while politicians liked to trumpet the visible benefits of their largess, there were often unseen costs and consequences that resulted from those policies.

It is a lesson that politicians should heed today.

Take, for example, Obamacare. The president loves to cite the fact that college students are now able to stay on their parents’ policies until age 26. This has undoubtedly made it easier for some students to get or keep insurance coverage. But the additional coverage is not free. In fact, according to the Department of Health and Human Services, the cost of continuing coverage from 18 to 26 could run as high as $3,400 per child per year. Much of that additional cost is passed back to companies that provide insurance coverage to dependents of their employees.

The predictable result: Companies are dropping dependent coverage altogether. Among them is one of the largest union-administered health-insurance funds in New York, SEIU United Healthcare Workers East, which is now dropping dependent coverage for 30,000 workers. Ironically, the fund had previously covered nearly 6,000 workers’ children, some up to age 23. Those students, along with other spouses and children, are now out of luck.