After churning through more than 12 years of litigation, three law firms, at least five dismissals and who knows how much cash, Norex Petroleum Ltd. finally caught a break on Thursday in its billion-dollar brawl with a gaggle of oil companies and Russian oligarchs.

Handing a big win to Barry Ostrager of Simpson Thacher & Bartlett, the New York Court of Appeals reinstated state law claims of tortious interference and unjust enrichment that Norex brought against BP plc, TNK-BP, Alfa Group Consortium, Len Blavatnik, Viktor Vekselberg and related entities. The decision clears up what the court described as a catch-22 involving three New York statutes that had crippled the case.