Earlier this week I wrote about the perils of the NRA’s single-issue politics. Now it’s breastfeeding moms in the crosshairs – different issue, same principle.

In the NRA case, it seems that they’re going after a Tennessee state legislator – a long-time NRA member and supporter, no less – who opposed a bill that would have allowed employees to keep guns in their cars while parked in their private employers’ parking lots. The principle at issue there could not be simpler or more basic to a free society: individuals, including private employers, should have a right to determine the conditions on which others may enter their property. The NRA’s mistake is in asking the state to restrict that right in the name of the Second Amendment, which of course applies only against governmental, not private, restrictions.

The breastfeeding moms make a similar mistake. We learn from NPR this morning that a number of them have just gathered en masse and staged a “Great Nurse-In” at the U.S. Capitol. Their aim is to secure “federal protection of breastfeeding everywhere.” Everywhere? In my home, my business?

Don’t get me wrong: I’m no more against the right to breastfeed than I am against the right to keep and bear arms. That’s not the point. Rather, the point is that, in a free society, the property right is fundamental, starting with your property in your person and your liberty, which you can exercise only to the extent that you respect the equal rights of others. Property rights set the lines that determine where one person’s rights end and the next person’s begin, which is why getting those lines right is so crucial to a society that aspires to protecting equal rights.

The breastfeeding moms might well object if they were forced to allow people to carry guns into their businesses, just as the gun owners might object to being forced to allow breastfeeding in theirs. And it isn’t that some values are better than others. We can argue over that all day and get nowhere. With rights, by contrast, there’s a good possibility of agreement. In fact, the nation is based on a live-and-let-live principle we largely agreed on at the outset – and lived by, for the most part, until we started asking government to impose our values on others, leading to the war of all against all that we see all about us today and to the politicization of everything, including parking lots and breastfeeding.