The Curse of Tippecanoe

In 1811, future president William Henry Harrison defeated Tecumseh at the battle of Tippecanoe. It is said that Tecumseh's brother, known as "The Prophet"
placed a curse on Harrison and the US presidency. In 1840, William Henry Harrison was elected president. He caught pneumonia during his inaugural speech and died a few months later.

1860: Abraham Lincoln was assassinated in his second term.
1880: James Garfield was assassinated in his first year of office.
1900: William McKinley was assassinated, too.
1920: Warren G. Harding died of a stroke during his first term.
1940: Franklin Delano Roosevelt died in his third term of a brain hemorrhage.
1960: Robert F. Kennedy was assassinated in his first term.
1980: Ronald Reagan was shot in the lung, missing his heart by less than an inch!
2000: George W. Bush was not elected by popular vote, but was elected by the electorial college.

Did the curse wear off? Was it thwarted by advances in the medical field, in Reagan's case? Is Bush in mortal peril? Or was there ever really a curse at all?