How common is it for members of the Republican Party to switch to the Democratic party?

I think it is fairly common for individuals to change from Republican to Democrat or from Democrat to Republican, and I have known a number who did. Sometimes it's a case of gradual evolution to the other side. Sometimes it's precipitated by events. I know several Republicans who could not support the George W. Bush war policies, the "weapons of mass destruction" issues, and came over to the Democratic party.

A famous, earlier D/R party switcher was Ronald Reagan, who was a Democrat during his time in Hollywood, was president of the Screen Actor's Guild (which is a kind of labor union), and later switched to the Republican party.

But switching for an elected official while in office is pretty rare:

  • In the history of the United States Senate, only one Republican Senator has switched to the Democratic party while a sitting senator. Arlen Specter of Pennsylvania, who became a Democrat in April, 2009.
  • However another Senator, Jim Jeffords of Vermont, changed from a Republican to an Independent in June, 2001, and caucused with the Democrats. In effect he became a Democrat.
  • Also, Senator Wayne Morse of Oregon moved from the Republican party to Independent in 1953, and then two years later in the next congress, moved on to become a Democrat in 1955-so a two step move.

Three R-to-D Senators total.

And in the other direction, three Democratic Senators have switched to the Republican party while a sitting senator:

  • Ben Nighthorse Campbell of Colorado, who became a Republican in March, 1995.
  • Richard Shelby of Alabama, who became a Republican in November, 1994.
  • Strom Thurmond of South Carolina, who became a Republican in September, 1964.

Three D-to-R Senators total.

There have been other switches, but not involving both of our current major parties. A hundred years ago, third party members of Congress were more common.

List of United States Senators who switched parties - Wikipedia

I'm sure it happens. But I'd like to see an accurate count of people who, like me, got disgusted with the Republican party and simply re-registered as independent or unaffiliated, without going the whole way and registering Democrat.

I can't really identify as Democrat. Back when I was a Republican, one of the reasons why is that the Democrats don't have all the answers, and that many of the ones that they do have are wrong. That doesn't change because I've had it up to here with the kind of people who've taken over the Republican Party, and what the ideology of it has devolved into.

My registration, over the last 4-5 years, as 'unaffiliated' rather than Democrat wasn't done out of apathy, confusion or lack of direction, it was reasoned and intentional. I simply quit believing in political parties. I refuse to accept being limited to only two choices.

Now, I reserve the right to call bullshit on either of them.

I would assume it is relatively uncommon although the Republican backing of trivial things like anti-abortion statutes, and status-quo marriage laws among other social problems probably sways some who see these issues as being highly important to them. I feel like the opposite is a change that is made much more often as people get older and start looking more into their financial interests rather than the social ones.
I was president of the nation's largest College Republican Club with two Aunts on the GOP national Committee both wanting to get me to run for Congress in their district.  So I was not a casual member in name only.   

I quit when the Republicans brought in a bunch of Southern bigots into leadership positions and started looking at more ways to limit Black voting.  The War on Drugs was a blatant attempt to put hippies and Blacks in jail and take away their votes forever.  Small government? More like prohibition without passing a Constitutional Amendment.
For N = me, 100%.
Not that uncommon at all. And neither is it uncommon for the switch to go the other way. Ronald Reagan was a Democrat, Hillary Clinton was a Republican. From the 50s to the 80s there was great upheaval in the south as the polarity on civil rights changed. Now, it seems more a political expediency thing. If a district changes, the incumbent changes with it.
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