Was Lincoln's performance as president in keeping with his previous political record?
In certain areas, yes, and in others, no. As a Whig in the Illinois State Legislature and later in the U.S. House of Representatives, Lincoln was a staunch advocate of internal improvements, a national banking system, and frontier settlement. During his presidency, he continued to support these causes, and implemented policies to further them. Additionally, he maintained a consistent opposition to the expansion of slavery. An unsuccessful bill to abolish slavery in the District of Columbia later became law during his first term as president. So, generally, with regard to domestic policy, Lincoln's presidency was of a piece with his previous political activity. The main difference between Lincoln the legislator and Lincoln the president lies in his attitude toward the balance of power between the executive and legislative branches of the federal government. As a Congressman, Lincoln had been extremely critical of President Polk's sweeping executive privileges during the Mexican War, arguing that only the legislature had the power to declare and direct the course of war. But during the Civil War, Lincoln himself usurped a considerable amount of Congressional authority, wielding more power than any president before or, arguably, since.
How did Lincoln transform the nature of the federal government?
Insofar as the Civil War was a battle to determine the balance of power between federal and state rights, the Union emerged from Appomattox with a much stronger federal government than ever before. Lincoln had a large hand in this, directing an elaborate military and policy campaign to keep the rights of the states in check. By declaring martial law in several areas above and beyond the authority of several state governors, by banishing and imprisoning numerous dissidents considered traitors to the federal cause, and by asserting and defending the policy that it was fundamentally impossible for the several states to separate from the Union, Lincoln augmented the powers of the federal government considerably. Through the passage of several domestic policies such as the Homestead, Land Grant and Pacific Railroad Acts, Lincoln strong-armed federal authority westward in the midst of the conflict, weakening the already diminishing position of the Confederate states. And finally, in the institution of the first income tax and the first issue of a national currency, Lincoln laid down a pair of economic cornerstones that continue to propel the federal government to this day.
To what extent was Lincoln responsible for ending slavery in the United States?
Slavery had been abolished in certain northern states during the late eighteenth century. By the time of the Civil War, only four of the states that remained in the Union, the so-called border states, continued to retain slavery. In the early stages of the war, Lincoln took a very conservative approach to the question of slavery, following the law to the letter by restoring numerous slaves freed during battle to their previous owners! Even his much- celebrated Emancipation Proclamation only applied to slaves in the Confederacy, and in fact had no direct bearing on slavery policy in what at that time remained of the United States. This proclamation freed very few slaves in short order, and what slaves were eventually freed during the war were liberated though the power of war rather than by executive decree. Lincoln ran for re-election in 1864 on the platform of an abolition amendment, and though such legislation was eventually seen through, it was months after Lincoln's death before his successor, President Johnson, signed the amendment into law. Thus, though Lincoln today stands as the obvious figurehead of the abolition movement, the end of slavery in the United States was a much more gradual and complicated process. Lincoln did much to encourage the final push toward emancipation, but he had several critics among the more radical abolitionists. In the end, Lincoln's contribution was more in the rhetoric than in the actual doing.