There’s been a controversy within Republican circles as to whether or not the GOP should strive to preserve popular aspects of Obamacare if the Supreme Court strikes down the law. In particular, Capitol Hill Republicans wonder whether or not the GOP should preserve Obamacare’s “slacker mandate,” which forces insurers to include adult children, up to the age of 26, in family coverage. But a federal mandate may not be necessary. On Sunday,UnitedHealth Group, the nation’s largest publicly-traded health insurer, announced that it would continue to include under-26 coverage in its family plans. Other insurers are likely to follow suit.