The two Maine lawyers who have a date with the nation’s highest court Monday morning say they’re both prepared for the rare experience – and one may wear his lucky tie.

George Isaacson and Matthew Schaefer of the Brann & Isaacson law firm in Lewiston are scheduled to appear before the U.S. Supreme Court at 10 a.m. to argue a case related to the collection of sales taxes by online retailers.

They are representing the Direct Marketing Association in its quest to knock down an earlier ruling by a federal appeals court that would allow Colorado to require out-of-state retailers, such as Amazon and L.L. Bean, to report their Colorado customers’ purchasing activity to the Colorado Department of Revenue.

For most lawyers, appearing before the U.S. Supreme Court is a once-in-a-career opportunity, and this will be the first time for both Isaacson and Schaefer.

“It is very exciting,” Schaefer said.

The case is being closely watched by business groups as the battle over online sales-tax collection continues among tax-hungry states, traditional big-box retailers, consumers and online retailers. The U.S. Chamber of Commerce, the National Federation of Independent Business and three other organizations have filed briefs with the court in support of the Direct Marketing Association. The National Council of State Legislatures and National Governors Association filed briefs in support of Colorado.

Brann & Isaacson specializes in representing online retailers – an outgrowth of its work with L.L. Bean dating back to the 1960s. Today it represents 25 of the top 100 online retailers in such matters as taxes, intellectual property and data security. The Direct Marketing Association is a New York and Washington, D.C., trade group representing online retailers and data-driven marketers.

For most lawyers, it’s a big deal to appear before the nine justices of the Supreme Court, which accepts only 70 of the 7,000 annual requests – not including those from prisoners – for review of lower court rulings. About 70 percent of the appeals to the court are handled by Washington lawyers.

“It was very gratifying and surprising,” Isaacson said of the court’s decision to review their case.

Isaacson will present the oral argument, probably while wearing his lucky tie. “It is one my family gave me,” he said.

A deputy assistant attorney general for Colorado will present the opposing side. Each side is alloted 30 minutes, during which the justices pose questions and the lawyers answer.

Isaacson and Schaefer are allotted six seats in the courtroom. Their family members and friends can watch if they are able to get in line early enough to snag one of the 100 to 200 seats reserved for the general public.

For Isaacson, the whole experience will provide a teachable moment for his constitutional law students at Bowdoin College in Brunswick. The audio of the session is recorded and will become available online soon after the arguments have concluded.

The two said they are not nervous because they have thoroughly practiced for their big moment. They had to file briefs setting out their arguments in cases in the past few months. They have held mock arguments with members from their firm standing in as the nine justices. And they have tried to anticipate every kind of question the justices could ask.

“We feel very strongly about our case,” Schaefer said.

The legal issue is somewhat arcane, involving a 2012 ruling by the 10th U.S. Circuit Court of Appeals. The ruling followed a federal District Court injunction that barred enforcement of a 2010 Colorado law that would have required out-of-state retailers – who under a 1992 federal law are not obligated to collect state sales taxes if they have no physical presence in the state – to provide the Colorado Department of Revenue with a list of their Colorado customers and their purchases.

Schaefer said the District Court found that the Colorado law – which he said is aimed at harassing online retailers into collecting sales taxes in Colorado – was unconstitutional because it discriminates against interstate commerce by requiring only out-of-state online retailers to provide their customers’ purchases.

The 10th Circuit Court reversed the District Court ruling, finding that the federal courts have no jurisdiction over a state’s tax laws under the federal Tax Injunction Act, which prohibits federal courts from restraining states from collecting their taxes.

Isaacson and Schaefer will argue Monday that the Tax Injunction Act was improperly applied by the 10th Circuit because the Colorado law concerns data collection, not tax collection.

Schaefer and Isaacson said their request for review was most likely granted by the Supreme Court to clear up divergent interpretations of the Tax Injunction Act on the federal District Court level.

The Supreme Court justices could discuss the case among themselves as early as next week, but a written decision is unlikely to appear until the spring at the earliest.