President Lincoln's 75,000 volunteers

On April 15, 1861, at the start of the American Civil War, the President of the United States, Abraham Lincoln, called for a 75,000-man militia to serve for three months following the bombardment and surrender of Fort Sumter. Some slave states refused to send troops against their neighboring states, with the result that most such states also declared secession from the United States and joined the Confederate States of America.

Background
In April 1861 the Regular Army of the United States of America consisted of approximately 16,000 officers and soldiers organized into ten regiments of infantry, four of artillery, two of cavalry, two of dragoons, and one of mounted rifles. These regiments were mostly posted in small forts of company-sized detachments, the majority posted West of the Mississippi River. Following the secession of seven states from December 1860 to the creation of the Confederate States of America in February 1861, many officers and soldiers resigned from the United States Army to join the Army of the Confederacy.

Legal limits
Until the early 20th century, the US relied on calling out militia and volunteers rather than expanding the regular army. However, there were restrictions on the number of men and the length of time they could serve that the President of the United States, as opposed to a State Governor, could summon. "Sec. 4. And be it further enacted, That the militia employed in the service of the United States, shall receive the same pay and allowances, as the troops of the United States, And that no officer, non-commissioned officer or private of the militia shall be compelled to serve more than three months in any one year, nor more than in due rotation with every other able-bodied man of the same rank in the battalion to which be belongs." – Militia Act of 1795

On March 2, 1799 the number of militiamen able to be called by the President of the United States for a provisional army was limited to 75,000 men.

Declaration
The declaration by Lincoln read:

Reaction and Resistance
Rather than a call for 75,000 military volunteers from any American state or territory, the two proclamations called for a specific number of volunteers from each state, including slave states in the South that had not yet declared their secession.

Several Northern states communicated enthusiasm, with states such as Indiana offering twice as many volunteers as requested.

Governor Isham Harris of Tennessee stated in a telegram to Lincoln, "Tennessee will furnish not a single man for the purpose of coercion, but fifty thousand if necessary for the defense of our rights and those of our Southern brothers."

Governor Beriah Magoffin of Kentucky declared that they would not send volunteers to a Northern army intent on subjugating their Southern brethren.

Governor John Letcher of Virginia, whose state had been requested to furnish three regiments totalling 2,340 men and officers, had stated in the past his intent for his state to remain neutral. He replied to Lincoln that since the latter had "chosen to inaugurate civil war, he would be sent no troops from the Old Dominion."

Governor Henry Rector of Arkansas stated, "The people of this Commonwealth are freemen, not slaves, and will defend to the last extremity their honor, lives, and property, against Northern mendacity and usurpation."

Subsequent actions
In early May, Lincoln gave a second call for an additional 42,000 men. On May 3 President Lincoln issued a further call for United States Volunteers to serve three years, with regiments to be organized by the state governments, unless sooner discharged. He increased the regular US army by 22,714 men and called for 42,034 more volunteers to enlist for three years. In July 1861, the U.S. Congress sanctioned Lincoln's acts and authorized 500,000 additional volunteers.