“The only good news for me is that sparkling wine is excluded,” Mr. Headrick said. “But 70 percent of my wine will be taxed.”

Many other importers will also face difficulties. David Bowler of David Bowler Wine in New York imports a lot of French wines, as well as German and Spanish bottles, which also will be taxed. But he also has in his import and distribution portfolio a fair number of wines from Portugal and Italy, which are excluded from the tariff, as well as wines from North and South America.

Mr. Headrick is that rare specialty importer whose portfolio will bear the brunt of the new tariffs. Most French wine specialists draw from around the country; they are likely to have producers in the southern Rhône Valley and Languedoc, where wines more often than not have alcohol levels above 14 percent.

“One of the ways I have been successful is keeping my head down and focusing on the Loire,” said Mr. Headrick, whose portfolio includes excellent producers like Domaine Vacheron of Sancerre and Damien Laureau of Savennières. “This is coming back to bite me.”

Why the seemingly arbitrary line of 14 percent? That’s a good question.

For decades the federal Alcohol and Tobacco Tax and Trade Bureau, which regulates taxes on alcoholic beverages, defined table wine as having a maximum alcoholic strength of 14 percent. Those beverages with 14 to 24 percent alcohol are considered dessert wines, and are taxed at a different rate.