Who was the more Libertarian candidate in past presdiential elections?

[tpfkaw]

A lot of these are difficult since both the candidates were very authoritarian.  I'm going to include independents with >5%.

As they governed/(I'm guessing) would govern, followed by as they campaigned:

2008: lean John McCain (R), lean Barack Obama (D)
2004: lean John Kerry (D) for both
2000: lean George W. Bush (R), George W. Bush (R)
1992/1996: Ross Perot (I, Ref) for both
1988: George H.W. Bush (R) for both
1980/1984: Ronald Reagan (R) for both.  1980 is a toughie.
1976: lean Gerald Ford (R) for both (a toughie)
1972: George McGovern (D) for both
1968: toughie, probably still Richard Nixon (R) for governing though an argument could actually be made for George Wallace (AIP), Richard Nixon (R) for campaigning (this is one of the most unlibertarian elections along with 88/00/04/08)
1964: Barry Goldwater (R) for both
1960: lean John F. Kennedy (D) for both
1952/1956: lean Dwight Eisenhower (R) for both
1944/1948: Thomas Dewey (R) for both
1940: Wendell Willkie (R) for both
1936: Alf Landon (R) for both
1932: Herbert Hoover (R), lean Franklin Roosevelt (D)
1928: Al Smith (D) for both
1924: Calvin Coolidge (R) for both
1920: Warren Harding (R) for both
1916: Charles Hughes (R) for both
1912: William Howard Taft (R), lean Woodrow Wilson (D)
1908: William Howard Taft (R) for both
1904: Alton Parker (D) for both
1896/1900: lean William McKinley (R) for both (though certainly WJB is the more libertarian option for Filipinos...)
1884/1888/1892: Grover Cleveland (D) for both
1880: Winfield Hancock (D) for both
1876: Samuel Tilden (D) for both
1872: Horace Greeley (D/LR) for both
1868: Horatio Seymour (D) for both
1864: George McClellan (D) for both
1860: John Bell (CU), lean Abraham Lincoln (R)
1856: lean John C. Frémont for both
1852: lean Franklin Pierce for both
1848: Martin Van Buren (FS) for both
1844: lean James Polk for both
1836/1840: Martin Van Buren for both
1832: lean William Wirt (AM) for both
1828: lean Andrew Jackson (D) for both
1824: lean William Crawford (DR) for both
1816: James Monroe (DR) for both
1812: DeWitt Clinton (F), James Madison (DR)
1808: James Madison (DR) for both
1796/1800/1804: Thomas Jefferson (DR) for both

[tpfkaw]

I agree with a lot of your reasoning, but what makes you think Eisenhower was more libertarian than Stevenson? I'm genuinely curious. Stevenson, after all, was the once calling for a nuclear freeze and a more diplomatic approach to the Soviet question. Ike also initiated the largest public works programme in human history.

Well Adlai was the candidate who wanted to continue the Korean War in 1952, and that colors my conception of him quite a bit.  This is also asking who was the more personally libertarian candidate, not who would govern more libertarian.  I suspect that if both of them had their druthers and could remake the US government from the ground up, then Ike's would be considerably more libertarian.

[tpfkaw]

I think a case can be made for Davis as even more libertarian than Coolidge considering Prohibition and trade.

Except that Coolidge was a wet and Davis was a dry...

Davis was the same or worse (from a libertarian perspective) as Coolidge on every issue except trade.