Considerations behind Confederate Gen. Robert E. Lee's campaign into Pennsylvania in the summer of 1863 include:

· His troops could live off the rich farmland in the North, not further taxing Virginia's resources during harvest time. His men could also forage for food and supplies and send these goods south.

· His movement would distract Union Gen. U.S. Grant's siege of a large rebel contingent at Vicksburg, Miss.

· The Union Army's own planning for a summer campaign - perhaps movement on the Confederate capital of Richmond - would be disrupted because it would have to chase down the rebels.

· If Union Gen. "Fighting Joe" Hooker's men followed Lee, defenses would be weakened around Washington, D.C., the heart of the Union war effort.

· If the rebels took Harrisburg, the capture of a major Northern city might give Democrats in the North leverage to force President Abraham Lincoln to negotiate a peace settlement.

If Harrisburg could be taken, leaders throughout the North knew that their town might be next.

· The invasion would disrupt rail and communication lines between the Midwest and the Eastern Seaboard or between the North and Washington, D.C.