The government of Switzerland filed an elegantly understated amicus brief for Judge Gold's consideration on Thursday (according to PACER) or yesterday (according to the media). The upshot of it is that enforcement of the United States' summons—which it implies (but refrains from outright saying) is just a "fishing expedition"—circumvents the applicable treaty and violates Swiss law. Here is the very abridged version:
The Government of Switzerland has a strong interest in the preservation of the integrity of Swiss law and sovereignty and in promoting respect by the United States of its international treaty obligations to Switzerland.
If the Court were to order UBS to produce evidence from Switzerland, and backed that order with coercive powers, the Court would be substituting its own authority for that of the competent Swiss authorities, and therefore would violate Swiss sovereignty and international law.The Wall Street Journal reports that an IRS agent speaking at a financial conference in Miami confirms that more "John Doe" summonses are in the works.