A close political election is often said to be “tight as a tick.” Television broadcast journalist Dan Rather (who frequently uses Texas expressions generally unknown to most of his viewers) has been credited with “tight as a tick” since at least 2000.
 
A tick attaches itself firmly to an animal and gorges itself on its host’s blood. “As full (of blood) as a tick”—usually meaning “drunk”—has been cited in print since at least 1678. “Tight as a tick” was originally used along with “full as a tick.”
 
A close basketball game was described as being “tight as a tick” in 1950. In 1968, Richard Nixon described his upcoming presidentia election as “tight as a tick.” The political use of “tight as a tick” became frequent in the 1990s. l
   
 
The Free Dictionary
tight as a tick
1. very tight. (Fig. on the image of a tick swollen tight with blood or of a tick stuck tightly in someone’s skin. *Also: as ~.) This lid is screwed on tight as a tick. The windows were closed—tight as a tick—to keep the cold out.
2. intoxicated. (Fig. on full as a tick. *Also: as ~.) The old man was tight as a tick but still lucid. The host got tight as a tick and fell in the pool.
3. [of a race] close, as if the racers are moving very closely together. (*Also: as ~.) This election is as tight as a tick.
4. very friendly and close; as thick as thieves. (*Also: as ~.) Those two are tight as a tick. They are always together.
McGraw-Hill Dictionary of American Idioms and Phrasal Verbs. © 2002
   
(Oxford English Dictionary)
tick, n.
Phr. as full (or tight) as a tick: full to repletion, esp. with alcoholic drink.
1678 J. RAY Coll. Eng. Proverbs (ed. 2) 284 As full as a pipers bag; as a tick.
1822 Yankee Phrases in New Jersey Alm. 1823 (Elizabethtown, N.J.) 31 Though of love I’m as full as a tick.
1911 L. STONE Jonah 226 ‘Ard luck, to grudge a man a pint, with ‘is own missis inside there gittin’ as full as a tick.
1933 M. LOWRY Ultramarine iv. 177 He was tight as a tick so couldn’t tell the difference.
1952 E. O’NEILL Moon for Misbegotten IV. 168 ‘You must have seen how blotto I was.’.. ‘I did. You were as full as a tick.’
1981 A. PRICE Soldier no More v. 59 He was drunk as a lord..tight as a tick.
   
Google News Archive
7 February 1950, Deseret News (Salt Lake City, UT), “Upsets, Pageant Feature Hoop Tourney Openers” by Jack Fairclough,  pg. 2C, col. 5:
It was tight as a tick all the way and the score was tied midway in the final canto until Buckway and Eva placed a winning surge.
 
8 August 1968, Pittsburgh (PA) Press, “Nixon Stereotypes Belie many-Sided, Gifted Poltician” by Richard Starnes, pg. 6, col. 6:
“It’ll be Nixon and Humphrey, and tight as a tick,” is how Mr. Nixon summed up the forthcoming presidential campaign to a visitor a month ago, “and whoever makes the fewest mistakes is going to win the election.”
 
Google News Archive
19 July 1969, Milwaukee (WI) Sentinel, “‘Shot’ May One Day Cure Ticks” by Maxwell Riddle, pt. 3, pg. 7, col. 2:
ONE of my correspondents wants to know where the expression “tight as a tick” originated. I don’t know just where that was, or when. Ticks have been around a long time, and they are undergoing a population explosion as great as that of man himself.
 
A tick buries its mouth parts in the skin. it won’t let go while feeding. So in pulling it off you are likely to leave part ofthe tick buried in the skin, where it festers.
 
I imagine that this observed fact brought about the expression “stick as tight as a tick.”
 
When a person is drunk, we also say he is “as tight as a tick.” A person who is very drunk is quite helpless. So is a tick which has engorged herself with blood. So maybe that is how the comparison was made.
   
2 September 1990, Newsday (Long Island, NY), “The Tune-up for ‘92’ -  Six key campaigns to watch in 1990” by Susan Page:
So far, the race is tight as a tick, though former San Francisco Mayor Dianne Feinstein’s initial lopsided support among women has diminished.
   
21 October 1990, Washington (DC) Post, “Taking Helms By the Tarheel” by Huntington Williams, pg. C1: 
The race is still tight as a tick. Barring a major misstep by either candidate or an “October surprise” (like a Persian Gulf war), the outcome will depend on two factors over which Helms has limited control-black registration and voter turnout.
       
17 October 1994,

, “Richards in ‘race of her life’; Texas gov faces tough challenge” by Mark Potok, pg. 8A:
“It’s tight as a tick,” says Bill Miller, a consultant who has worked with both parties.
 
New York (NY) Times
THE 1994 CAMPAIGN: Virginia The Last Weekend: Senate Races Where the Battle Has Been Intense; You Needn’t Ask: North Is Confident
By MICHAEL JANOFSKY,
Published: November 6, 1994
RICHMOND, Nov. 5— Throughout the turbulent Senate race in Virginia, Oliver L. North has usually let his confidence speak for itself.
 
But with a new poll that shows him trailing the Democratic incumbent, Charles S. Robb, by 39 percent to 31, Mr. North called a news conference today, three days before the election, to say how confident he felt and predict that he would win by at least three points.
(...)
Mr. Robb hailed the findings of the new poll. “We’re surging,” he said. “Our own polls show we’re up by six points. We are aware of the fact we’ve been moving. You can feel it.” “My sense is that it’s tight as a tick,” said Larry J. Sabato, a professor at the University of Virginia. “No one I know in either campaign thinks this is anything but close.”
 
Ace of Spades HQ 
February 17, 2005
“Frankly, we don’t know whether to run, to watch, or to bark at the moon” (Hoke)
CBS plans tribute to Dan Rather
Rather, 73, will talk about last fall’s ill-fated “60 Minutes Wednesday” story about President Bush’s military service, said Susan Zirinsky, the show’s executive producer. CBS fired the story’s producer and asked for the resignations of three executives because it could not authenticate documents used in the story.
 
In a 60 minute tribute (minus 18 minutes for Metamucil, Cialis and Depends commercials), that should be just enough time for “Well, Mary’s a great gal, and we thought it was a tight story. Tight as a tick. Spandex tight. Other than that, well . . . I’m just sorry it turned out to be shakier than cafeteria Jell-O.”
 
The Corner on National Review Online
Thursday, January 26, 2006
A Close Race?  [Rich Lowry ]
Another note on the majority leader race. It’s important to remember how it works. It is possible for this thing to be “tight as a tick,” as Dan Rather would say, even if the vote counts don’t make it look like it is (Blunt 92, Boehner 49, Shadegg 16).
         
Language Log
December 21, 2007
Couric on the primaries: too close to call, tight as a tick
(...)
Then the next night, Couric opened the Evening News broadcast with a teaser about a close primary race in another state:
 
The first presidential battle in the South. A new poll shows it’s tight as a tick in South Carolina between Clinton and Obama.
(...)
Couric’s other turn of phrase, “tight as a tick,” might actually have a more distinct CBS provenance, since it’s widely attributed to her predecessor Dan Rather (known for his colorful Texanisms):
 
The new Iowa Polls show the caucus fights are “tight as a tick,” as Dan Rather might say. (Des Moines Register, Dec. 1, 2007)
 
The conclusion to be drawn from this mass of data is that—in the words of Dan Rather—it is “tight as a tick” in Iowa. (Washington Post blog, Dec. 7, 2007)
 
In 2000, CNN host Jeff Greenfield attributed a more elaborate version to Rather:
 
And yet, either because of the challenger’s appeal or the insider’s weakness or maybe, maybe, because of an enduring American hunger for the new, this contest remains tight as a tick in Grandma’s corset. I have no idea what that means, but it works for Dan Rather. (CNN transcript, Oct. 31, 2000)
(...)
And in the last presidential election cycle Gordon Fischer, the chairman of the Iowa Democratic Party, used yet another variant on the Fox News show “Big Story with John Gibson”:
 
Well, you know, frankly from the polls, this is looking as tight as a tick on a deer. (Fox News transcript, Jan 19, 2004)
 
“On a deer” is an interesting variation on the theme, since a quick Google search finds the tick appearing chiefly in canine locations, in accordance with Rather’s 1996 usage: on a hound, bloodhound, hound dog, coon dog, dog, dog’s ear, dog’s back, etc.
 
Though Rather tends to get the credit for “tight as a tick” with reference to close political races, it’s a regional idiom with a wide array of other possible meanings. These meanings have lately been dissected on the American Dialect Society mailing list, in a discussion sparked by Couric’s recent usage. Darla Wells, who first caught the broadcast, was familiar with the sense of “tight as a tick” meaning ‘having had too much to drink,’ and Dennis Preston collected this sense for his 1975 article, “Proverbial comparisons from southern Indiana” (Orbis 24,1:72-114). Ron Butters, meanwhile, suggested the idiom could mean ‘miserly,’ with tight related to tightwad. Finally, Gregory McNamee supplied some local knowledge from the region of Virginia where Couric was raised, saying that “tight/full as a tick” in that area refers to someone who has overeaten, “gorged to the point of popping, like a tick full of blood.”
(...)
Posted by Benjamin Zimmer at December 21, 2007 01:11 AM
 
Washington (DC) Post - The Fix by Chris Cillizza
GA-Senate: Tight as a Tick
By Chris Cillizza |  November 25, 2008; 11:20 AM ET
The Georgia Senate runoff between Sen. Saxby Chambliss (R) and former state Rep. Jim Martin (D) appears headed to a close finish, a narrowness that is ramping up the pressure on President-elect Barack Obama to make a visit in the state sometime between now and Dec. 2.
 
Three new polls released on Monday suggest the race is tight.
 
Ace of Spades HQ
May 17, 2010
White House Bracing for Specter Loss
—Ace
(...)
The primary is, as Dan Rather says, tight as a tick, 42% Sestak 41% Specter.