This week marks the 150th anniversaries of the Union triumphs at Gettysburg and Vicksburg. Both victories were pivotal, signaling the beginning of the end of the Civil War. Thereafter, the Confederacy would fight a defensive war closing with Lee's surrender at Appomattox less than two years later. Abraham Lincoln and many northerners believed that the Union's twin wins were providential, coming as they did around Independence Day (the Vicksburg surrender, in fact, came on July 4).

In the America of 2013, the fight against insults to and assaults on liberty continue. As the Founders keenly appreciated, liberty is always pressed and challenged in every generation, to one degree or another. Freedom is a natural but fragile right; it survives and flourishes only when defended -- fiercely at times.

The north's Pennsylvania and Mississippi battlefield successes gave teeth to Lincoln's Emancipation Proclamation (issued in the autumn of 1862 in the wake of the Battle of Antietam). The proclamation, contrary to popular thinking, didn't free all the slaves, but those held in rebel states (or those states still in rebellion by January 1, 1863). Slave Border States siding with the Union were exempted. Lincoln, ever the shrewd politician and leader, needed to keep the Union states together to finish the bloodiest conflict in the nation's history. Slavery would be done away with by the 13th Amendment shortly before the war's end, Lincoln being a prime instigator of the amendment.

Today, more than at any times since the Revolution and Civil War, freedom is under attack. Call it the Long War on Liberty. This war has been waged by the American left, conventionally and unconventionally, for decades. The battlefields aren't Bull Run or Chancellorsville or Chickamauga or Cold Harbor. They're many and varied, less straightforward and more sinister. The leftist enemies of freedom long ago found artful ways to cloak themselves in the mantle of freedom. They are deceivers of a high order.

During Barack Obama's presidency, the war on liberty has accelerated and intensified. Never before has the American left been so brazen in its aims: to grow the state and its powers, while diminishing freedom. Should the left triumph, America as conceived will cease to exist.

There is a culmination coming to this war on freedom; a great storm has been slowly gathering. How this war resolves itself and when -- and what its full contours will be -- are very much open questions. But come the storm will. To paraphrase Lincoln, America cannot endure half-slave and half-free. Either tyranny prevails or is vanquished. Either freedom is made regent again or is extinguished.

Liberty-loving Americans -- those who embrace traditional America, an America of God-given natural rights, an America of limited government -- have yet to coalesce, to find their footing and true voices, to gather as one mighty force to defeat those among us who wish to overturn the American experiment in freedom.

Slavery was an insult to liberty -- a grievous challenge -- from the nation's inception. The Founders knew this, but the American republic could never have arisen had the Founders' sought to outlaw slavery then. By the 1860s, though, the North was strong enough to fight a war that began with a cry to preserve the Union but ended with freedom for millions of black men, women, and children. The abomination of slavery -- this ongoing, festering insult to human dignity and freedom -- was excised once and for all. America, having destroyed slavery, became truer to its founding principles.

We Americans are being tested again today; challenged to form a more perfect union through the defeat of a new tyranny. The left is the new enslavers. Will they succeed in their awful designs?

Let's close with Lincoln's Gettysburg Address:

Four score and seven years ago our fathers brought forth on this continent, a new nation, conceived in Liberty, and dedicated to the proposition that all men are created equal.

Now we are engaged in a great civil war, testing whether that nation, or any nation so conceived and so dedicated, can long endure. We are met on a great battle-field of that war. We have come to dedicate a portion of that field, as a final resting place for those who here gave their lives that that nation might live. It is altogether fitting and proper that we should do this.

But, in a larger sense, we can not dedicate -- we can not consecrate -- we can not hallow -- this ground. The brave men, living and dead, who struggled here, have consecrated it, far above our poor power to add or detract. The world will little note, nor long remember what we say here, but it can never forget what they did here. It is for us the living, rather, to be dedicated here to the unfinished work which they who fought here have thus far so nobly advanced. It is rather for us to be here dedicated to the great task remaining before us -- that from these honored dead we take increased devotion to that cause for which they gave the last full measure of devotion -- that we here highly resolve that these dead shall not have died in vain -- that this nation, under God, shall have a new birth of freedom -- and that government of the people, by the people, for the people, shall not perish from the earth.

Amen.