12 July 2006 by Published in: Union Cavalry 10 comments

Last night, I promised that I would address the difference between a covering force action and a defense in depth, and why I am now persuaded that the tactic used by John Buford at Gettysburg was actually a covering force action and not a defense in depth. Here goes…..

I find it easier to use modern military definitions to define these terms. Even though they use modern parlance and anticipate modern weaponry, they still apply equally well to Civil War tactics.

The Pentagon defines a defense in depth as this: “The siting of mutually supporting defense positions designed to absorb and progressively weaken attack, prevent initial observations of the whole position by the enemy, and to allow the commander to maneuver the reserve.”

In other words, a defense in depth requires that a defender deploy his resources, such as fortifications, field works and military units, both at and well behind the front line, falling back from one defensive position to another, with the whole idea being to suck the enemy in so that he exposes his flanks to attack. The strategy is especially effective against an attacker who is able to concentrate his forces to attack a small number of places along an extended defensive line. It employs the deployment of force in mutually supportive positions. In other words, the idea is to force the enemy to drive the defender from each chosen position and inflict casualties upon him in the process.

A recent U. S. Army manual defines a covering force action thusly: “The covering force operates independently from the main body. The purpose of covering force operations is to develop the situation early and deceive, disorganize, and destroy enemy forcing. However, unlike screening and guard forces, a covering force is tactically self-contained and often seeks to become decisively engaged with the enemy. Cover operations are performed in the offense or defense and can be conducted by either the ACR or separate brigade.

There is no clear line between the covering force battle and the main battle. Covering forces continue to operate in some areas, while the main battle is pursued in others. Throughout the operation, battles shift from defensive action in one locale to offensive action. That is why the ACR or separate brigade conducting a covering force mission must be prepared for either mission.

When a covering force action begins, the main body generally is not engaged. Depending on how much warning it gets, and the mission of the main body, the covering force can be heavily augmented with engineers, MI, and artillery before the battle begins. With less warning, support arrives with the battle already underway. In any event, the covering force is expected to continue resistance until the corps has had time to deploy. Because it operates independently from the corps main body, the MI company must be able to move all of its personnel, systems, and equipment with its own organic assets.”

In other words, the idea behind a covering force action is to trade time for space, thereby allowing a detached forward unit (usually cavalry) to delay the advance of the enemy long enough to permit the main body to come up and engage. The covering force will operate independently of the main body.

Two examples of defenses in depth come to mind. General Daniel Morgan designed and implemented an excellent defense in depth that was used to great effect at the Battle of Cowpens. This tactic, which used militia to draw in Tarleton’s men, then exposed them to a galling fire from the main line and then to a cavalry charge into the flank. Nathanael Greene used the same tactic effectively at Guilford Court House, although Greene was eventually defeated.

In the Civil War, Lt. Gen. William J. Hardee designed a defense in depth very similar to–some say inspired by–Morgan’s defense in depth at Cowpens that he used effectively at the Battle of Averasboro on March 16, 1865. Hardee, with less than 10,000 men, was able to hold off half of Sherman’s army for an entire day by using a well-designed defense in depth. He used three prepared defensive positions to do so, falling back from each one as he was driven from them, until he ultimately reached the third, and final, line. By that time, it was dark, and Sherman didn’t have the stomach to attack that line. Hardee then pulled out during the night.

What John Buford designed and implemented at Gettysburg was a classic example of a covering force action, one that was, in fact, such a perfect textbook example of one that it’s taught as a staff ride by the Army to this day. The whole idea was to trade three ridge lines worth of space for time to permit Reynolds and First Corps to come up and engage. Buford’s tactic delayed the Confederate advance for nearly five hours on the first day of the Battle of Gettysburg.

Having studied all of this in much greater depth, I came to the conclusion that my prior assertions about Buford using a defense in depth was just plain wrong, and I’ve said as much publicly many times. It was, indeed, a perfectly designed and perfectly executed covering force action.

Scridb filter


  1. John D. Mackintosh
    Thu 13th Jul 2006 at 8:43 am

    Great food for thought, especially the real-life examples cited– the contrast between our nearby Cowpens and what Buford did at Gettysburg.

  2. Thu 13th Jul 2006 at 8:57 am

    You are correct, in modern terms, altho I don’t think there was any sort of published doctrine in the CW about this. Buford sort of made it up because he intuitively grasped the situation. That series of parallel ridges offered him great ground to do it on.

    Having been professionally trained as a cavalryman and a staff officer, I can affirm that the cavalry in the defense has three missions: screen, guard, and cover. In the CW screening missions were the most common, guard missions almost nonexistent, and covering force actions rare. I can only think of three or four, but then I have not read nearly as much about the subject as you.

    Period tactics did allow for an advance or rear guard, often a mixed force, that often operated independently or semi-independently as a covering force, and there are a number of late-war examples of the Confederates using their sharpshooters this way.

  3. Thu 13th Jul 2006 at 9:11 am

    Thanks, John. Glad you found something of use there.


  4. Thu 13th Jul 2006 at 9:14 am


    You are correct, of course, but what’s interesting to me is how little things have changed over the years. Standard NATO doctrine, back in the days of the Cold War, were to conduct a covering force action at Fulda Gap in the hope of holding back the Soviet armor long enough for the main body to come up. Although there weren’t horses involved, the tactics were identical.

    We’ve actually identified about a dozen examples of good covering force actions conducted during the war. The other most famous one was Minty’s brigade at Chickamauga in September 1863, but Dibrell’s division of Hampton’s cavalry fought an outstanding one at Bentonville on March 18, 1865.


  5. Thu 13th Jul 2006 at 10:18 am

    Yup. I was in the 14th (later the 11th) Cavalry in Fulda, and our mission was very similar to Buford’s at Gettysburg — to slow down the Russkis long enough for the bulk of V Corps to arrive. Was over there a couple of years ago and everthing has completely changed — except for a 1km stretch preserved as a museum, you’d have a hard time telling where the border was.

    The big difference now is the addition of tanks to the cavalry, which gives it a fighting capabilty that it just did not have in the ACW. Thus guard missions (which involve fighting) are much more common, as is the use of the armored cavalry regiments for covering force actions.

    Thus a modern FM on cavalry tactics will still serve as a reasonably good guide for the CW, as long as you understand the differences in equipment and terminology. Our instructors used several CW examples in class and were at some pains to emphasize that cavalry tactics had changed little in 200 years.

  6. Thu 13th Jul 2006 at 11:35 am


    And that’s precisely the point I was trying to make.

    US armor fought a heck of a covering force action against the Iraqis during Gulf War I, and it plainly demonstrates that the more things change, the more they remain the same.


  7. Lance Herdegen
    Thu 13th Jul 2006 at 1:31 pm

    As always, I enjoyed your assessment of John Buford’s role in the July 1 cavalry action and agree with it. I am biased, of course, but I have always believed Buford’s defense and the fighting to hold McPherson and Seminary Ridges won Gettysburg for the Union. One has only to look at the killed, wounded and missing lists for the entire three days see the truth of it.

  8. Dave Powell
    Fri 14th Jul 2006 at 6:20 am


    Three cheers! I have always been bugged by people referring to Buford’s action as a defense in depth – I still see it called that by lots of people. Glad you have been pursuaded.

    One helpful way to think about a Defense in Depth is that the defenders actually don’t intend to shift position much – the idea instead, especially under the modern definition – is to instead form hardpoints that the enemy will choose to bypass rather than attack head-on. Bypassing, however, means that the enemy attack force is divided and channelled into prepared kill sacks that become traps. The defender can then commit reserves to eliminate enemy spearheads one at a time.

    Covering forces rarely stand and fight, their job instead is to trade space for time and identify the primary thrust to higher command, who can then decide where and how to meet the attacker.

    Dave Powell

  9. Fri 14th Jul 2006 at 9:00 am


    That’s very good stuff–thanks for passing that along.


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