Politicians usually take all opponents seriously—or, at least, they usually say that they do, even if an election is sure to be a lopsided victory. “There are two ways to run for office—scared or unopposed” is an old political adage of uncertain origin. John Glenn, while running for re-election as the U.S. Senator from Ohio, said in 1980 that there were two ways to run for political office:

“One is unopposed and the other is scared. I have opposition.”


16 September 1980, The Plain Dealer (Cleveland, OH), “A quiet campaign pits Betts, Glenn; both going all-out,” pg. 7-A, col. 1:
COLUMBUS (AP)—John H. Glenn won his U.S. Senate seat by more than a million votes six years ago, but he’s not taking lightly his chances for re-election Nov. 4.
(...)
Glenn says there are only two ways to run for office.

“One is unopposed and the other is scared. I have opposition,” he said.

Google Books
Collision:
How the Rank and File Took Back the Teamsters
By Kenneth C. Crowe
New York, NY: Scribner’s
1993
Pg. 175:
At the outset of the campaign to gather the signatures at the end of May 1990, Burke, in his down-home style, told Carey, “Ron, the old saying is there are only two ways to run for office. Either run unopposed or hard and scared. We got to run hard.”

5 October 1995, The Post-Standard (Syracuse, NY), “Challenger sparks hostility: Republican Ian Hunter is running against Democrat Sam Roberts, who has hel the seat for six years” by Mike McAndrew, City sec. pg. 3, col. 4:
As for Roberts’ approach to this campaign, the legislator said there are only two ways to run for public office: unopposed or scared.

Google Books
The U.S. Congress:
A Very Short Introduction
By Donald A. Ritchie
New York, NY: Oxford University Press, Inc.
2010
Pg. 28:
Incumbents say that there are only two ways to run for reelection: scared, or unopposed.

Twitter
AU College Democrats
‏@AUCollegeDems
There’s two ways to run a campaign: scared or unopposed. I’m going to be opposed - Jim Himes @jahimes #aucdhimes http://twitpic.com/40l3b9
7:52 PM - 16 Feb 2011

Twitter
Lisa Villa
‏@replisavilla
My friend told me “if you are running for office there are only two ways to run, unopposed or scared.” I guess I’m running scared. #FTW
8:59 AM - 19 Oct 2012

WAPT (Jackson, MS)
Barbour opens up to 16 WAPT’s Bert Case
Former Mississippi governor sits down for no-holds-barred interview
By Bert Case
UPDATED 10:00 PM CDT May 19, 2014
RIDGELAND, Miss. —16 WAPT’s Bert Case sits down for a no-holds-barred, one-on-one interview with former Gov. Haley Barbour.
(...)
“In politics there is an old adage: There are two ways to run: Scared or unopposed,” Barbour said.