The problem is that if you hold a strict interpretation of the butterfly effect (or even a loose one, really), the first president changing will logically result in the likelyhood of pretty much all of the modern politicans possible for the 2004 election dropping to zero...
1789 - Benedict Arnold (Independant)
1792 - Benedict Arnold (Independant)
1796 - Alexander Hamilton (National Republican)
1800 - Samuel Adams (Democratic Republican)
(1803 - Aaron Burr (Democratic Republican) (Acting President))
1804 - Alexander Hamilton (National Republican)
1808 - John Marshall (National Republican)
1812 - John Marshall (National Republican)
1816 - John Marshall (National Republican)
(1819 - DeWitt Clinton (National Republican) (Acting President))
1820 - DeWitt Clinton (National Republican)
1824 - William H. Crawford (Democratic Republican)
1828 - William H. Crawford (Democratic Republican)
1832 - William Wirt (Nationalist)
(1834 - Daniel Webster (Nationalist) (Acting President))
1836 - William Smith (Democratic)
1840 - John C. Calhoun (Democratic)
1844 - Daniel Webster (Nationalist)
1848 - John C. Calhoun (Democratic)
1852 - Winfield Scott (Democratic)
1856 - John Fremont (Nationalist)
1857 - Military Coup against Fremont. Robert E. Lee (D) installed as President.
1860 - Lee confirmed as President by military fiat on his side in ongoing Civil War, Fremont confirmed by election in states under his control. War ends in 1862 with Fremont as President.
1864 - Benjamin F. Butler (Nationalist)
1868 - Benjamin F. Butler (Nationalist)
1872 - Benjamin F. Butler (Nationalist)
1876 - Benjamin F. Wade (Nationalist)
1880 - Lafayette S. Foster (Nationalist)
1884 - Lafayette S. Foster (Nationalist)
1888 - Allen G. Thurman (Nationalist)
1892 - Adlai Stevenson (Nationalist Party)
1896 - Roger Wolcott (Independant)
1900 - William J. Bryan (American Labor)
1904 - Alton B. Parker (National American Party)
1908 - Eugene V. Debs (American Social-Labor Party)
1912 - James M. Cox (National American Party)
1916 - James M. Cox (National American Party)
1920 - James M. Cox (Independant- NAP Dissolved)
1924 - Edward L. Logan (National Party)
1928 - Edward L. Logan (National Party)
1932 - Smedley Butler (Military Coup to prevent ASLP Victory)
1934 - Elections Suspended
1938 - Elections Suspended, Butler replaced by Douglas C. MacArthur
1942 - Elections Suspended
1948 - Elections Suspended
1952 - Vincent Hallinan (Progress Party)
1956 - Vincent Hallinan (Progress Party)
(1955 - George Wallace (Progress Party) (Acting President))
1960 - George Wallace (Progress Party)
1964 - Nelson Rockefeller (Commerce Party)
1968 - Hubert Humphrey (Progress Party)
1972 - Nelson Rockefeller (Commerce Party)
1976 - George McGovern (Progress Party)
1980 - George McGovern (Progress Party)
1984 - Walter Mondale (Progress Party)
1988 - Donald Rumsfeld (Commerce Party)
1992 - Albert Gore, Jr. (Progress Party)
1996 - Ralph Nader (Progress Party)
2000 - Ralph Nader (Progress Party)
2004 - Mitt Romney (Commerce Party)