During Lee's invasion of Pennsylvania in 1863, Parker supplied several organized regiments of New Jersey volunteers that were sent to protect that state, but when a levy of 12,000 men was made on New Jersey in 1864, to make good a supposed deficiency in her former quotas, he obtained from President Lincoln the withdrawal of the order. In 1863, Parker attended the ceremonies dedicating the Soldiers' National Cemetery at which Lincoln delivered the Gettysburg Address. Parker established a method of settlement of the war debt so that not a bond of the state of New Jersey was sold below par, and at the close of the war in 1865 there was a surplus of $200,000 in the state treasury.