THEY say you can’t fight city hall. If the tenor of yesterday’s hearing at the Supreme Court is any indication, it seems you can’t fight the Rathaus either. The case pits a Californian woman, Carol Sachs, against OBB Personenverkehr BB, a railway owned by the Austrian government. In March 2007, Ms Sachs went online and bought a ticket for train travel in Austria and the Czech Republic from Rail Pass Experts (RPE), an outfit in Massachusetts authorised to sell Eurail passes. A month later, when attempting to board a train in Austria operated by OBB, Ms Sachs fell between the platform and the train and landed on the tracks. Her legs were crushed by the moving train, requiring a double amputation. Ms Sachs then filed a lawsuit in a federal district court in California in which she accused OBB of negligence, design defects and breach of implied warranties.

Ms Sachs says the train began rolling just as she was stepping on board; OBB counters she recklessly attempted to mount the train when it was already moving. But this factual dispute is beside the point. The Supreme Court’s question in OBB Personenverkehr AG v Sachs BB is whether Ms Sachs even has a right to sue the Austrian rail company in America. According to long-standing international custom, governments cannot be summoned to court in another country. This doctrine of “sovereign immunity” was codified, and modified, in the Foreign Sovereign Immunities Act (FSIA) of 1976. FSIA establishes some exceptions to blanket immunity. To prevent governments from escaping responsibility for negligent treatment of foreigners in the marketplace, the law lifts sovereign immunity “insofar as their commercial activities are concerned.” A “foreign state engages in commercial activity,” the statute says, "where it acts ‘in a manner of a private player within’ the market”.

Ms Sachs claims that since OBB was engaged in “commercial activity” in America through an agent, Rail Pass Experts, it loses immunity to lawsuits and must be held to account for her accident. The railroad responds that “the RPE is not an authorised agent of OBB, nor does it have any legal relationship with OBB.” The commercial activity exception does not apply, OBB insists, because “the only commercial activity within the United States was the plaintiff’s purchase of the travel ticket online through a United States travel agency over which the foreign railway exercised no control and to which the foreign railway gave no direction.”

In the hearing on October 5th, the justices seemed reluctant to let Ms Sachs’s transatlantic lawsuit go forward. No one contested that buying the Eurail pass in the United States amounts to some form of commercial activity. But the question became whether, in Justice Sonia Sotomayor’s words, clicking through the website and entering credit card information was “substantial enough” to fall under the FSIA exception and therefore make OBB potentially liable for Ms Sachs’s injuries. Juan Bosombrio, arguing for the railroad, argued that the bulk of the commercial activity in question occurred on Austrian soil.

In search for clarity on this question, Chief Justice John Roberts posed a hypothetical question. “[L]et's say you have a flight from New York to Vienna. And in New York, someone negligently sets or whatever they do with the landing gear, okay? So then the plane takes off. And then in Vienna, because of the negligence in New York, it's a rough landing, somebody gets a concussion...Can you bring that in the United States?” In such a case, Mr Bosombrio responded, the passenger with the concussion could in fact sue the airline in America because “the foreign airline came here and conducted a commercial activity in the United States”. But since OBB runs no trains inside the United States, he argued, it cannot be held to account in America for commercial activity conducted entirely in Europe.

When Jeffrey Fisher, Ms Sachs’s lawyer, took the lectern, he faced a round of tough questions. Justice Ruth Bader Ginsburg began with a reality check: “There is one contact with the United States. A pass is bought from a travel agent in Massachusetts, a pass covering 30­-odd railroads. That's all that happened in the United States. All of the relevant conduct, the tortious conduct occurred abroad.” Before Mr Fisher could fully respond, Justice Elena Kagan chimed in with another hypothetical question involving the Vienna Opera House. If she bought opera tickets while in America and then “slip[ped] in a puddle” while attending an opera, would she be eligible to sue in an American court? Mr Fisher said no, but his attempt to distinguish the opera from the railroad did not seem to persuade anyone on the bench.

Ms Sachs is free to sue the railroad in Austria under Austrian law, but the justices seem concerned that allowing Ms Sachs to press her case in an American court would undercut the spirit of FSIA and subject foreign governments to all manner of lawsuits based on the most tenuous of commerical associations. Given how tightly interwoven governments and markets are in today's global reality, the subject of Justice Stephen Breyer's new book, a ruling favouring Ms Sachs could gum up international relationships in unpredictable, and potentially undesirable, ways.