There have been numerous political defections in U.S. history by politicians that were motivated by one reason or another to make their switch across the aisle.
Whether it be in last ten years or one hundred years ago, here is a list ranking the top 10 political defections in U.S. history:
10. Jim Jeffords, 2001:
When the "Contract for America" was being discussed in 1994, and Newt Gingrich with his congressional Republicans were uniting behind the issue along with impeaching then-President Clinton, Republican Jim Jeffords was not on the same bandwagon. Jeffords was one of the few (if not only) Republican critic of the Republican-backed Contract for America, and he was one of only five senate Republicans to vote against impeaching President Clinton. Being frustrated with what was transpiring in the Republican Party, he left the party in 2001 to become the only Independent senator on Capitol Hill. With Jeffords leaving the Republicans to be an Independent, he arguably brought the Republican Party back towards the political middle.
9. Wendell Willkie, 1939:
Wendall Willkie was for the most part a liberal Democrat who decided to seek the Democratic presidential nomination in 1932. When he went up against FDR in the Democratic primary race, he lost and decided to go into business working for one of the largest utility companies in the country. While working at that company, he turned into an anti-New Deal and anti-FDR fan, so he decided to join the Republican Party and won the party's nomination for president in 1940 (he ended up taking a whooping in the general election). Willkie flipped parties again to support FDR's WWII policies shortly thereafter, only to run for president against FDR as a Republican in 1944. Republican leadership at the time didn't get fooled again...
8. Richard Shelby, 1994:
After butting heads with President Clinton numerous times over different pieces of legislation (voting against the Democrat majority on almost every issue), Shelby switched to being a Republican because he felt it was the better party for America's future. His switch of parties gave the Republicans a 53-47 edge in the Senate, so his defection changed the tide of political power. He was widely-popular in his home state of Alabama, and that popularity has allowed for him to still be a Senator to this day even though he switched political parties.
7. Theodore Roosevelt, 1912:
Shortly after Roosevelt's second term as president finished, he decided to try his luck and run for an unprecedented 3rd term for president. Once William Howard Taft won the nomination on the Republican side instead of Roosevelt, he decided to try his luck with his own political party known as the Progressive Party (otherwise known as the Bull Moose Party). He lost to Democrat Woodrow Wilson in the general election, but did beat out Taft in the popular vote.
6. Strom Thurmond, 1964:
In 1948, Thurmond ran for president as a racist Democrat who was trying to keep non-whites out of the lives of Caucasians. By the time the Civil Rights movement and Martin Luther King Jr. came around in the 1960s, most of his fellow Democrats disagreed with his mindset so he left the Democrats to become a Republican. With his switch to becoming a Republican and being a senator of South Carolina, it helped the GOP turn a normally blue state into a red one.
5. Arlen Specter, 2009:
After four terms of being a Republican Senator, Specter decided to switch parties and run for re-election in 2009 as a Democrat. He had left his Democrat affiliations in 1965 to run local office in his home district as a Republican, and in 2009 he went back to his roots. Unfortunately, the party switch prior to his election did not win him over any votes and he ended up losing his bid for re-election.
4. Condoleezza Rice, 1982:
Condoleezza Rice is most famously known as working in President George W. Bush's administration. She claims that the Jim Crow law Democrats of the South not letting her dad vote when she was younger helped motivate her to eventually switch to being a registered Republican. However, in her first election being able to vote, she was a registered Democrat who voted for Jimmy Carter. It was the handling of foreign affairs issues by then President Carter that motivated Rice to vote for Reagan in 1980 and join the GOP in 1981.
3. Michael Bloomberg, 2001:
Being the life-long Democrat that Bloomberg was for most of his life, he felt that the Democratic Party was too entrenched with politicians who had been there for too long so in 2001 he decided to run for New York City Mayor as a Republican (and ended up winning). After raising money for presidential campaigns of the likes of George W. Bush and others, Bloomberg officially left the Republican Party in 2007 to become a registered independent and signify a possible run for president in 2008 -- which he never fulfilled. In 2009, he was actually on the ballot for Mayor in New York City as both a Republican and an Independent.
2. Hilary Clinton, 1960s:
Hilary Clinton was there to campaign for her husband and Democrat former President Bill Clinton, ran for President as a Democrat, and currently is the Secretary of State for Democrat President Obama. What many people don't know about Hilary, is that she used to be a hardcore Republican. When she was a teenager, she canvassed and campaigned for Republican Richard Nixon for President. She worked for Republican Barry Goldwater's campaign in 1964, and was even elected president of Wellesley College's Young Republicans club. Due to issues like the Vietnam War however, Hilary left the Republican Party to help candidates like Eugene McCarthy and George McGovern. Imagine the current political atmosphere if she never had a change of heart to switch parties in the early 1970s...
1. Ronald Reagan, 1962:
With probably the most significance of any politician on this top 10 list, former President Ronald Reagan tops this list of most significant political defections in U.S. history in my opinion. While Reagan was president, he was known for his preaching of limited government and fiscally-conservative principles to help guide the U.S. economy through what was the tail end of a tough 1970s period of stagflation. In his youth though, Reagan was a strong FDR New Deal supporter along with campaigning for Democratic Senate Candidate Helen Douglas in 1950 and trying to push Dwight D. Eisenhower to run for president in 1952. While he worked for General Electric however, his political views started to shift to the right to where we now have come to know them today (even after his death).