Texas opposed the bar owner’s trademark application, arguing that it would lead consumers to believe it was sponsored by the General Land Office and that it tarnished the state “by communicating that the heroism and sacrifice undertaken by its forebears is not worthy of memory or esteem,” the agency wrote to the trademark appeals board. Texas won that fight, too: “I Can’t Remember the Alamo” underwear was never sold because the bar owner, Christopher Erck, abandoned the trademark application.

“It got fairly heated, I will say that,” Mark Dallas Loeffler, the communications director for the General Land Office, said of the dispute. “In the end, I think he realized it was probably more trouble than it was worth just to sell a shirt. In our opinion, it was a victory for the State of Texas. The people of Texas should have the right to protect the phrases that are iconic to Texas.”

To protect “Don’t Mess With Texas,” state transportation officials and lawyers monitor what they call “the usage of the brand.” The slogan was coined in 1985 by Tim McClure, a native Texan and a founder of GSD&M, an advertising agency based in Austin and hired by the state to help its antilittering campaign reach the worst highway offenders — men under 25. The phrase gave rise to a state-sponsored Web site, a book (“Don’t Mess With Texas: The Story Behind the Legend”), a Twitter account, television advertisements, bumper stickers and trash cans, all of which, if you look carefully enough, are emblazoned with the tiny encircled “R” that signifies a registered trademark.

“The phrase is known around the world, and it is important for everyone to recognize that ‘Don’t Mess With Texas®’ means ‘Don’t litter,’ ” Veronica Beyer, a Transportation Department spokeswoman, said in a statement. “When an alleged infringement is discovered, the department quickly seeks the appropriate legal remedy, which is usually a cease-and-desist demand of the unauthorized use and all future uses thereof. In the majority of such cases, our request for the violator to cease and desist has been all the action required.”

One group should not worry about using the phrase, however. The state’s politicians never tire of dropping it into speeches. As governor, George W. Bush used it in his speech accepting the Republican presidential nomination in 2000, and the state’s attorney general, Greg Abbott, recently used it when campaigning for governor. State and federal law allow for trademarked phrases to be used in political speech, said Megan M. Carpenter, the director of the Center for Law and Intellectual Property at the Texas A&M University School of Law in Fort Worth.

Gov. Rick Perry traveled to New York in June to try to lure businesses to Texas. A television ad tied to his trip that criticized New York as a high-tax, high-regulation state — paid for by the marketing group TexasOne, which also paid for the governor’s trip — tweaked the trademarked “I ♥ NY” logo to read “NY ♥ regulations.” New York, so far, has let it slide.