Stuart D. Gibson and Richard D. Euliss – I have no idea what you Tax Division guys look like. But the brief you filed Tuesday in the UBS AG tax case is so muscular, so righteous, so full of passion …. so, dare we say, sexy?

Sure, you gave the filing in Miami federal court a demure title, Memorandum of Law In Support of Petition to Enforce “John Doe” Summons. But it’s really a big extended middle finger from the Tax Division to the Swiss government and whomever (note: probably the State Department) leaked to the New York Times that the U.S. was considering dropping one of its most important tax-evasion cases ever. The table of contents comes out blasting:

•  UBS BROKE THE LAW AND HELPED U.S. TAXPAYERS EVADE THEIR TAXES
•  UBS KNOWINGLY HELPED ITS U.S. CUSTOMERS COMMIT TAX EVASION
•  UBS PRIVATE BANKER USED STEALTH TO AVOID DETECTION

And so on.

The confrontational language sure suggests the U.S. won’t settle this civil suit without getting what it demands: the names of 52,000 Americans suspected of hiding assets from the IRS in Swiss-based UBS accounts. Jack Blum, a Washington lawyer who specializes in tax evasion investigations, said UBS is “the best case on the facts the U.S. government will ever have.”

Blum added: “The precedent is essential. UBS subjected itself to U.S. jurisdiction through its conduct. Give up here, and it’s Game Over for IRS.”

Indeed, the brief by Gibson, a senior litigation counsel, and Euliss, a trial attorney, states: “The United States has a vital national interest in maintaining the integrity of its system of taxation.”

The brief paints a portrait of arrogance on the part of UBS. Its bankers “lied on Customs forms – claiming to be in the United States for pleasure … and conducted their business under the radar.”

The bank “openly and notoriously” helped U.S. citizens evade taxes and “secretly and consistently violated with impunity” a Qualified Intermediary agreement to disclose foreign and U.S. beneficial owners of its accounts.

UBS trained its bankers in “spycraft” and “illegally” sent them into the U.S. to “troll” for customers, the brief says.

You can read the 55-page filing here.

To step back for a moment: The U.S. is cracking down on tax havens. In February, UBS admitted under a deferred prosecution agreement that it routinely violated U.S. law by recruiting U.S. clients to put assets in offshore accounts, and by filing paperwork to hide its crimes. The bank disclosed as many as 300 U.S. clients identities to the government and agreed to pay a $780 million fine.

A former UBS executive, Bradley Birkenfeld, earlier pleaded guilty to defrauding the U.S. and is reported to be cooperating with federal investigators.

The U.S. pursuit of UBS has ignited a diplomatic uproar in Switzerland, whose whole economy revolves around being a tax haven for the world’s wealthy. The Swiss cited a tax treaty with the U.S. to argue it could not breach its stringent bank secrecy laws.

The brief drips with contempt for UBS’s argument that by signing the tax treaty, the U.S. was essentially saying it was in America’s national interest not to press the Swiss in such delicate matters.

“It is, to put in mildly, presumptuous for a foreign bank that has engaged in serious criminal conduct in the United States to suggest what is in the best interests of the United States,” the brief said in footnote 49.

Then there’s UBS’s argument that the IRS should only get information on customers the bank has acknowledged were engaged in criminal conduct. The brief says that “would be tantamount to the convicted bank robber arguing that he should be given credit for all the times he walked into a bank and didn’t rob it.”

And to UBS’s argument it always acted in “good faith” to comply with U.S. law, the brief bellows: It “bears all the hallmarks of an eleventh-hour confession, made in the hopes the sinner will be absolved from the full consequences of his wrongdoing.”

 “It is time for UBS to face … the consequences it has brought on itself,” the government said.

Acting Assistant Attorney General John A. Dicicco of the Tax Division was also on the brief. U.S. District Judge Alan S. Gold has scheduled a July 13 hearing on the U.S. request for the UBS client names. For UBS’s response read this Associated Press story.