While most historians tend to dismiss him in favor of more "activist" presidents, I wish to afford his proper place as one of the centerpieces of the Jacksonian movement of the 1830s and 40s.
So let's review some of his achievements in office. influence and territory, Van Buren opposed any further empire building.
The first, and most laudatory, was his peaceful foreign policy. He was also successful in preventing two wars with Mexico and the U. by maintaining a neutral stance that promoted free trade over mercantilist conflict.
He also opposed the annexation of Texas for fear it would divide the party over the slavery question (and boy was he right about that! This was a trait seen during the Jackson administration, when he successfully negotiated a trade settlement with the British West Indies, and prevented a war with France over Jackson's hot temper.
Martin Van Buren is probably one of most maligned, and paradoxically one of the most forgotten United States presidents.
However, in his time, he was one of the biggest forces to occupy the Democratic Party.