Zachary Taylor's presidency was too short-lived to have substantially impacted the office or the nation. He is not remembered as a great President. Most historians believe that he was too nonpolitical in a day when politics, parties, and presidential leadership demanded close ties with political operatives.

Taylor's "outsider" philosophy kept him out of touch with Congress. He never addressed the legislature with a clear policy statement, nor did he use his influence to direct legislation—except on the matter of statehood for California and New Mexico. He thought that the President's role should be limited to vetoing unconstitutional legislation and that otherwise he should give in to Congress on matters of domestic concern. What he said about federal economic policy in his only annual message to Congress was utterly ignored due to preoccupation with the territorial issue. In foreign policy, his treaty with England on Central America, the Clayton-Bulwer Treaty, is recognized as an important step in scaling down the nation's commitment to Manifest Destiny as a policy. Yet many of his political contemporaries thought that it went too far in respecting England's claim to power in the Americas.

Overall, Taylor was something of an anomaly. He was a slave owner who wanted to ban the expansion of slavery into the western territories that had been acquired from Mexico. He was the triumphant military conqueror of Mexico who saw little need for Manifest Destiny as a foreign policy. He was an army general who shied away from war as an instrument of state. He was a stern military commander who avoided decisive actions as President. The one thing about him that is clear is that he was committed to preserving the Union even if it meant using force against the secessionists.

It is interesting to speculate what might have happened had Taylor lived and been elected to a second term. On the political front, Taylor, at the time of his death, was under severe pressure from Whigs to replace his unpopular cabinet, and had he done so, it might have improved relations with the congressional wing of the Whig Party. More importantly, had he lived, there might not have been a Compromise of 1850 or even the Civil War. Because the South was still too disunited in 1850 to form a viable secession movement, Taylor's unflinching support (had he lived) for the immediate statehood of the western territories might have changed the course of history. He had surprised many when he stamped out Santa Anna at the Battle of Buena Vista. The question remains: If Taylor had survived, would he have been able to stamp out the most burning issue that faced the nation in 1850—the expansion of slavery westward?