“I don’t have a dog in that fight”
President George Bush and political advisor and cabinet member James Baker (both from Texas) have been credited by William Safire for using “I don’t have a dog in that fight” in the 1980s and 1990s. It means “I don’t have an interest in this matter.”
The first recorded citation of ““Ain’t got no dog in this fight” is in 1982 from Tennessee’s Howard Baker, then the Senate’s majority leader. It is not known where or when the saying originated.
Wikipedia: Idioms
Have a dog in the fight/race To have a stake in, or be exposed to the risks associated with, the outcome of some problem or dispute. Conversely, “I don’t have a dog in that fight” is frequently used as a way to beg off and opt out of being expected to assist
28 March 1982, New York (NY) Times, “Howard Baker trying to tame an unruly Senate” by Martin Tolchin, Magazine, sec. 6, pg. 17:
Midnight had passed, and the Capitol was all but deserted, the echoes of occasional footsteps reverberating on tile floors. Outside room S230, the office of the Senate majority leader, a dozen reporters clustered, awaiting word from within where a dozen Congressional leaders were in a deadlock on a major budget item with an Administration group that included James A. Baker 3d, the White House chief of staff; David A. Stockman, the budget director, and Treasury Secretary Donald T. Regan. The reporters milled about impatiently, missing deadlines, until finally the door opened just a crack to reveal the majority leader himself, Tennessee’s Howard H. Baker Jr.
(...)
Last year, for example, when Senator Slade Gorton, Republican of Washington, wondered why the majority leader was sitting out a debate, Mr. Baker offered one of his down-home epigrams: “Ain’t got no dog in this fight.”
21 August 1984, Washington Post, pg. A9:
DALLAS, Aug. 20—Vice President Bush today gingerly sidestepped questions about the financial disclosure problems of Rep. Geraldine A. Ferraro (D-N.Y.), saying, “I don’t have a dog in that fight.”
8 April 1995, Elyria (OH) Chronicle-Telegram, pg. C8?:
More honestly, the party chief (Haley Barbour—ed.), who’s trying to play traffic cop among at least eight GOP presidential candidates, says: “I am not as dumb as I look .. I ain’t got a dog in that fight.”
23 October 1996, New York Times, pg. A25:
How do New Yorkers pick a dog in this fight?
10 May 1997, Syracuse (NY) Post-Standard, pg. C11, col. 3:
“As they say here in Texas, we don’t have a dog in that fight.”
7 March 1999, New York Times, pg. BU1:
WHEN Wall Street competitors start growling and snapping at one another, the safest place for the general public is usually a good block away. As the folks down home would say, we probably don’t have a dog in that fight.
16 February 2003, New York Times, pg. WK11:
After a recent U.N. session on the Iraq crisis, I asked a Bush aide how China was behaving. “The Chinese?” the official said. “They don’t think they have a dog in this fight.”
New York Times
10 December 2006, New York Times, Sunday Magazine, “On Language” by William Safire:
“I don’t have a dog in that fight” has long been a favorite Texas saying of former Secretary of State James Baker (now cuttingly called “acting secretary of state”).