“A campaign for re-election is a referendum on the incumbent”

A popular political adage is that a re-election campaign is “a referendum on the incumbent.” The challenger is looked at secondarily, but the primary focus of an election is the incumbent’s record in office. If there is no incumbent running, the saying may be applied to the candidate who represents the political party that has the incumbency.
 
“Any re-election campaign is inescapably a referendum on the incumbent” has been cited in print since at least December 1981. The saying is frequently used during presidential election years.
 
   
Wikipedia: Incumbent
The incumbent, in politics, is the existing holder of a political office. This term is usually used in reference to elections, in which races can often be defined as being between an incumbent and non-incumbent(s). For example, in the 2004 United States presidential election, George W. Bush was the incumbent, because he was the president in the current term while the election sought to determine the president for the following term. A race without an incumbent is referred to as an open seat.
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When newcomers vie to fill an open office, voters tend to compare and contrast the candidates’ qualifications, issues positions and personal characteristics in a relatively straightforward way. Elections featuring an incumbent, on the other hand, are as Guy Molyneux puts it, “fundamentally a referendum on the incumbent.” Voters will first grapple with the record of the incumbent. Only if they decide to “fire” the incumbent do they begin to evaluate whether the challenger is an acceptable alternative. At the same time, if the challenger is determined to be wholly unacceptable, voters might reluctantly vote for the incumbent.
 
6 December 1981, The Times-Picayune (New Orleans, LA), “‘Referendum’ on Morail” by Allan Katz, sec. 1, pg. 26, col. 1:
Any re-election campaign is inescapably a referendum on the incumbent, and the coming New Orleans mayoral campaign will be a vote for or against the perceived capabilities and character of Ernest Nathan Morial.
     
Google Books
National Journal
Volume 15, Part 4
1983
Pg. 2200:
That is a formal way of stating what most politicians know: that every presidential election is a referendum on the incumbent. Even if the incumbent is not running, the election is a referendum on his record in ofiice.
   
Google News Archive
7 October 1984, Modesto (CA) Bee, “With month to go, it’s hard to tell it’s election year” by Ed Salzman, pg. B7, col. 2:
He said the presidential contest is “a referendum on the incumbent” and it would be difficult for any challenger to defeat a president like Reagan “when the incumbent is perceived to be doing well.”
 
16 September 1992, Valley Independent (Monessen, PA), “‘Keys to campaigning’ split on ‘92 race,” pg. 6A, col. 1:
WASHINGTON—Now here’s a sobering thought for pollsters and other players in this year’s presidential election.
 
Campaigns don’t matter. The debates, commercials, bus tours and speeches between now and Election Day count for virtually nothing.
 
At least that’s the conclusion of Ken DeCell and Allan J. Lichtman, co-authors of a book called “The 13 Keys to the Presidency.”
 
DeCell, a senior editor at Washingtonian magazine, and Lichtman, a history professor at American Univesity, argue that a presidential campaign isn’t the horse race it’s generally made out to be. Instead, the election is essentially a referendum on the incumbent administration’s record.
 
New York (NY) Daily News
Give Mccall Four More Years
Monday, October 26, 1998
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Bruce Blakeman, McCall’s Republican opponent, is an intelligent, articulate public servant. He helped form the Nassau County Legislature in 1995 and is its presiding officer. But an election is a referendum on the incumbent, and Blakeman’s arguments for replacing McCall are not persuasive.
   
National Review Online
November 4, 2006 11:30 A.M.
Code Blue in Minnesota
How a rising Republican star finds himself in a tough fight for reelection.
By Scott W. Johnson
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If the adage that a campaign for reelection is a referendum on the incumbent applied, Pawlenty would win going away.
   
Nashua (NH) Telegraph
Sunday, September 25, 2011
Obama looking better against ‘alternative’
By CARL LEUBSDORF
One of the most persistent political maxims is that a presidential re-election campaign is a referendum on the incumbent.
 
That doesn’t augur well for President Barack Obama – at least not based on recent trends and polls.