However, Herman Hattaway and Archer Jones wrote that the "strategic impact of the Battle of Gettysburg was ... fairly limited." Steven E. Woodworth wrote that "Gettysburg proved only the near impossibility of decisive action in the Eastern theater." Edwin Coddington pointed out the heavy toll on the Army of the Potomac and that "after the battle Meade no longer possessed a truly effective instrument for the accomplishments of his task. The army needed a thorough reorganization with new commanders and fresh troops, but these changes were not made until Grant appeared on the scene in March 1864." Joseph T. Glatthaar wrote that "Lost opportunities and near successes plagued the Army of Northern Virginia during its Northern invasion," yet after Gettysburg, "without the distractions of duty as an invading force, without the breakdown of discipline, the Army of Northern Virginia an extremely formidable force." Ed Bearss wrote, "Lee's invasion of the North had been a costly failure. Nevertheless, at best the Army of the Potomac had simply preserved the strategic stalemate in the Eastern Theater ..." Furthermore, the Confederacy soon proved it was still capable of winning significant victories over the Northern forces in both the East (Battle of Cold Harbor) and West (Battle of Chickamauga).