It's Independence Day, so many Americans are reflecting on the year 1776, when this nation was born. But today's rancorous political divisions are also a reminder of 1861, when President Lincoln explained in a Fourth of July speech why war was necessary to crush that period's "states' rights" movement.

More than 150 years later, another crew of states'-righters are challenging a president. They're not threatening to secede, but are vowing to ignore a law passed by Congress and recently deemed constitutional by the U.S. Supreme Court — the Affordable Care Act, which they have derisively dubbed Obamacare.

The most vocal of the law's critics tend to be governors of some of the same rebellious Southern states Lincoln named in his 1861 address to Congress, when he announced that the functions of the federal government had been "generally suspended within the several states of South Carolina, Georgia, Alabama, Mississippi, Louisiana, and Florida."

But opposition to the health-reform law isn't limited to the South. New Jersey Gov. Christie is a loud foe, which, given his state's generally liberal tilt, is more evidence that many of the attacks on the ACA have more to do with partisan politics in a presidential election year than anything else.

Gov. Bobby Jindal of Louisiana, which has some of the poorest, most medically underserved people in this country, says he won't accept additional Medicaid assistance, which would be largely paid for by the federal government for 10 years, if it means accepting President Obama's reforms.

The fact that Louisianans, New Jerseyans, and others who would benefit from the ACA are buying politically inspired rhetoric trashing it should remind people of all those men who never owned a slave but were persuaded by politicians and other elites to fight a Civil War over the Southern states' perceived right to preserve slavery.

Lincoln acknowledged the Constitution gives the states certain rights, but they aren't sovereign. He said the states' only legal status resides in the Union because the Union created them. Union isn't used anymore to refer our nation. But with as much division as there is now, union must be our goal.