Although many military leaders on both sides were not deluded by thoughts that the Civil War would be short, they usually assumed that it could be fought by limited means, rather than requiring the massive mobilization of men and resources that it eventually did.  General Winfield Scott promoted a strategy for the Union to surround the Confederacy by blockading the Atlantic, Gulf of Mexico, Mississippi River, and Ohio River, and await its surrender when the resultant hardships became unbearable.  The Union press derided his suggestion as the "Anaconda Plan" (after the snake), and questioned his loyalty to the Union for seemingly not wanting to invade his native state of Virginia.

The Confederate Congress was set to convene in Richmond on July 20, 1861.  On June 26, the influential New York Tribune began to run a prominent editorial-page slogan that urged Union troops:

The Nation's War-Cry!

Forward to Richmond!  Forward to Richmond!  Forward to Richmond!

The Rebel Congress must not be allowed to meet there on the 20th of July! 

By That Date The Place Must Be Held By The National Army!

With editor Horace Greeley at home recuperating from a knee injury, this saber rattling was initially approved by managing editor Charles A. Dana.  With Greeley's blessing, it remained the Tribune's editorial headline through July 4, a crucial period in the planning of the Union's military strategy.  Other Northern newspapers echoed the "Forward to Richmond!" charge.  

On May 24, President Lincoln had directed Union troops to enter Virginia and occupy Arlington and Alexandria, situated just west across the Potomac River from the nation's capital.  After the Virginia troops withdrew, Elmer Ellsworth, organizer of the Chicago Zouaves volunteer unit and a personal friend of Lincoln's, was killed while taking down a secessionist flag.  A Tribune correspondent ran a sensational story on the incident, and other newspapers picked it up, feeding the frenzy for a march to Richmond.

By this time, the president was ready to take a chance.  Lincoln ordered General Irvin McDowell, commander of the 35,000 Federal troops in the Washington vicinity to launch an assault on the Confederates at Manassas Junction, Virginia.  Located near Bull Run Creek, between the two capitals, the Confederate troops were commanded by Generals P. G. T. Beauregard and Joseph E. Johnston.  The Confederate press had been agitating for a similar "On to Washington!" strategy, which Beauregard was planning until he learned that McDowell was already set to attack him.

On the day of the battle, July 21, 1861, politicians, other notables from Washington society, and their wives, packed picnic baskets and drove to the hills around Manassas to witness the defeat of the Confederacy.  McDowell’s attack at Bull Run Creek almost succeeded, but the Confederates stopped a last strong Union assault.  Under General Thomas Jackson, who resisted the Union advance "like a stone wall" (and was thereafter known as "Stonewall" Jackson), the Confederates counterattacked, screaming the "rebel yell" at the top of their lungs.  

Already haggard by the battle in which nearly 3000 of their compatriots died, a wave of panic issued through the Union troops, who retreated in a rout back to Washington, along with the ladies and gentlemen of Washington society.  However, the heavy losses also suffered by the Confederate side (nearly 2000) prevented their pursuit of the Federals.  In the wake of Manassas/Bull Run, Lincoln increased the size of the army, and both sides learned the lesson that it was not going to be a quick and easy war.