MADISON, Wis. (CN) – Two household names in beer argued before a federal judge Thursday over the veracity and potential harms of Bud Light advertisements claiming Miller Lite and Coors Light contain high-fructose corn syrup.

MillerCoors filed its lawsuit in March, stating that an ad campaign concocted by rival Anheuser-Busch misled consumers into believing that Miller Lite and Coors Light, two of MillerCoors’ flagship products, contain the sweetener in an attempt to irreparably harm MillerCoors’ products in the crowded beer marketplace and increase the sales of Anheuser-Busch’s Bud Light.

The case, presided over by U.S. District Judge William Conley in Madison, Wisconsin, alleges that the million-dollar advertisements, which featured billboards as well as prominent TV commercials during this year’s Super Bowl and Academy Awards, are meant to purposely confuse consumers since MillerCoors does not use high-fructose corn syrup, a sweetener found in hundreds of products that is increasingly being linked to obesity, cardiovascular disease and colorectal cancer.

Instead, MillerCoors says it uses a very different product – plain corn syrup – in its fermentation process, which is completely consumed by the yeast and therefore absent in the final beverage. The company is asking for injunctive relief under the Lanham Act enjoining the ads, some of which have already been discontinued.

Donald Schott, counsel for MillerCoors from the Madison branch of nationwide firm Quarles & Brady, argued Thursday that the ads play off the preconceived notion that consumers do not like corn syrup, fear its unhealthy drawbacks and do not want to consume it, thereby damaging MillerCoors by implying that Miller Lite and Coors Light contain it.

Judge Conley was quick to point out that “if this were a case about intent, you would probably win,” but that the protections against intent claims in Seventh Circuit precedent may not prove to be enough for the case to survive on those merits alone.

MillerCoors admits it uses plain corn syrup in certain aspects of the brewing process but that it is a falsehood to state that the finished beer product contains corn syrup.

The gray area between advertisements that seek to surreptitiously promote a common misunderstanding, getting consumers to make logical leaps to alter brand loyalties, and comparing ingredients and brewing processes between products were discussed at length during Thursday’s arguments.

Conley posed the question early on whether “susceptibility to misunderstanding” is in itself a violation of the Lanham Act.

Schott offered that “true statements that give a false impression are actionable under the Lanham Act,” going on to say that “you don’t have to say the bad thing in order to the draw the impression of the bad thing.”

The judge wondered if it was enough for relief “without some more disparagement” for Anheuser-Busch to state something that is technically accurate – that MillerCoors uses corn syrup and Anheuser-Busch does not – in a way that may intentionally mislead consumers, or at least not correct an existing misconception.

James Bennett, an attorney with St. Louis firm Dowd Bennett representing Anheuser-Busch, did not think so, considering it “only a literally true statement” that corn syrup is a listed ingredient in Miller Lite and Coors Light.

Bennett stated that the ads “only intended to point out the difference between the more natural ingredients” in Aheuser-Busch’s products as compared to MillerCoors’ beers.

Conley did take exception with one billboard used in the ad campaign that stated that Bud Light contains “100% less corn syrup” than MillerCoors’ products, calling it “misleading in the extreme.”

“It would be like saying there is 1,000% less radon,” in the products, the judge said.

Bennett noted that the billboard and all others like it have been discontinued and taken down, or are at least in the process of being taken down.

But Bennett did back up Anheuser-Busch’s strategy of only using terminology that MillerCoors itself uses such as “brewed with,” “made with,” and “use,” and that the light-hearted tone of the campaign does not have any outright negative statements or non-verbal cues.

Schott opined during his rebuttal that “the reputational damage [MillerCoors] has seen is the very definition of irreparable harm,” citing surveys of recent sales figures.

Both Bennett and Conley questioned the substance and sample sizes referenced, however, with Bennett pointing to different sources and stating that MillerCoors has actually reported increased sales and market share since the ad campaign commenced.

Conley indicated at the close of arguments Thursday that he anticipates issuing his decision sometime next week.