Best President from 1829-1860

[OSR stands with Israel]

I would definitely go with Polk here

[Yellowhammer]

James Buchanan because he facilitated Southern secession. Polk is second.

[darklordoftech]

Would have been Harrison had he lived longer.

[SWE]

If you don't say Taylor then your opinion doesn't count

[MASHED POTATOES. VOTE!]

Taylor.

[RINO Tom]

All terrible or forgettable.  Buchanan and Johnson are easily the worst ... perhaps Polk or Taylor for the best.

[Orser67]

Polk. The Mexican-American War may not have been ethical, but the annexation of California certainly worked out for the U.S. in the long term. And he handled the partition of Oregon well enough.

He was also probably the most effective domestic policy president of the period, too. The Independent Treasury System that he revived stayed in place for 70 years and the tariff reduction bill was also a pretty big deal. And unlike Jackson, his presidency didn't end in a financial panic.

[Lechasseur]

I would definitely go with Polk here

[Mr. Reactionary]

Tyler or Polk

[fhtagn]

I would definitely go with Polk here

[UlmerFudd]

I would definitely go with Polk here

[YE]

I would definitely go with Polk here

[TDAS04]

Taylor.

Would have been Harrison had he lived longer.

He was still better than most of them.

[Atlas Has Shrugged]

I would definitely go with Polk here

[Unconditional Surrender Truman]

Easily Taylor. Adoration for Polk usually stems for blind valuation of "effectiveness" over actual policy merits —the presidency revealed him to be even more of an imperialist hack than the "Manifest Destiny" slogan implied, and by the end of the Mexican-American War his demands had grown so unreasonable that his ambassadors had to basically ignore his directives in order to settle the peace negotiations. He was still better than most of these by virtue of being somewhat competent, but I'll take the man who was prepared to veto the Fugitive Slave Act over the man who provoked an unnecessary war with a weaker power any day.

[OSR stands with Israel]

Without Polk the Southwest and all of California would not be part of the US and the US would be far weaker without the region

[Sestak]

Taylor was the only president there who wasn't 100% pro-slavery.

Polk comes in second.

Buchanan dead last.

[Fuzzy Bear]

Andrew Jackson, albeit with reservations.  While Jackson was, indeed, a racist, the Senate was 1/2 slave state, 1/2 free state during Jackson's tenure, as part of the 1819 Missouri Compromise, and this had an impact.  Jackson was more effective in preserving the Union and minimizing intersectional strife than any other President.

The pick of Taylor by Harry S. Truman is interesting.  Taylor had more guts than any President in that period save Jackson, and he may well have saved both the Union and the Whig Party had he lived, but, likely, at the expense of slavery continuing beyond what it did.