By incorporating that belief into treatment, with particular attention to the spine, chiropractic care may be able to provide pain management for back pain patients using a variety of methods to achieve that goal.
US Presidents are elected by the Electoral College. However, there were six Presidents who served in office without being endorsed by popular vote. Gerald Ford was one of them; he became president after Richard Nixon resigned in 1974, and was not elected at the end of the term. The other part of the question is a trick. George Washington was never elected by popular vote, but he was elected by the Electoral College (like all Presidents) in 1789 and 1792.
The last President of the US who was neither Democrat or Republican was Millard Fillmore (1850-1853), who was a member of the Whig party. One could argue that the last (and only) President who wasn't a member of any political party was George Washington.s was also pointed out, the last non Republican or Democrat to become president was Millard Fillmore. You could also argue that John Tyler and Andrew Johnson (as mentioned by Andrew Stein) were not really affiliated with a party while they were in office.