James Knox Polk is the best one term president, and a top 10 overall president. Lets consider his presidency on several issues:

Goals: One of the main ways to judge whether a president is a good one, is whether or not he accomplished what he set out to do. Polk set four goals for his presidency:
1. reestablish the independent treasury system.
2. reduce the tariffs
3. acquire some or all of the Oregon Territory
4. acquire New Mexico and California from Mexico
---Another big part of his goal was to acquire Texas, but that was done a week before he was inagurated, so that is not included.

He accomplished all of these goals with the Walker Tariff, and restored the independent treasury system. So on these he is two for two.

The big issue with James Knox Polk is the Mexican War and the idea of manifest destiny.

Polk was such a huge Jacksonian Democrat that he earned the name "Little Hickory" to Andrew Jackson's "Old Hickory". I believe though that Polk was a far better president than Jackson. Andrew Jackson was personally responsible for the deaths of many Native Americans on the "Trail of Tears". Also though, his personal fight with the Bank of the United States had a direct effect on Panic of 1837.

The annexation of Texas was strongly supported by Polk, and the people of the independent Republic of Texas. As such, Texas was added to the United States in 1845. Mexico has no say in whether Texas becomes part of the United States or not, Texas won their independence from Mexico almost 10 years earlier and governed themselves. Mexico threatened war if Texas was annexed, despite having no say in the matters of Texas or the US. When Polk sent a representative down to Mexico to negotiate the peaceful purchase of New Mexico and California(which Mexico had severely neglected), he was not allowed entry. They thought that the US was going to compensate Mexico for the "loss" of Texas. As such, he is seen as starting a "pre-emptive" war with Mexico. In reality, the war with Mexico was going to be inevitable, it was just a matter of who started it first. And when the US won, they took California and New Mexico, but still paid Mexico a fair amount of money. Polk later peacefully negotiated the Gadsden Purchase with Mexico to set the southwest boundary where it is today.

Contrary to popular belief, Polk was not a warmongerer in the vein of Napoleon and Hitler. This is illustrated in his purchase of the Oregon Territory, the Gadsden Purchase, and fighting the clamoring in his own party to annex all of Mexico and Cuba, which he refused. He merely knew what it took to protect the United States from other aggressors in the area. Unlike in Europe, where boundaries for those nations had been set for hundreds of years, the North American continent was still very unorganized and in a lot of places, there were conflicts of who owned what. For example, the Rio Grande was claimed by both the US and Mexico, and the entire Oregon Territory was claimed by Britain and the US. These were going to come into conflict eventually it was just a matter of time. Polk merely carved out what was to be the US and what was not. If that sounds unreasonable, it is really not. Not only could he have taken all of Mexico, at least all of the Oregon Territory, and Cuba, but there was significant numbers of Democrats that were demanding that that be what he do, just as a start. He showed his strength in resisting these overtures.

He is widely recognized as the last strong president before Lincoln. But he is also known as the first strong US war president. His taking of the reigns for the Mexican War also set the precedent that Lincoln would follow in the Civil War.

For that, it is my opinion that he is a top 10 president in my opinion. The only thing that he may have been able to do that would have made him a top 5 or even top 3 would have been to take a stronger stance on slavery. But hey, you can't win them all I guess.

My top 10 presidents:

1. Lincoln 2. FDR 3. Washington 4. T. Roosevelt 5. Jefferson 6. Eisenhower 7. Polk 8. Wilson 9. Truman 10. Adams