In a win for Facebook, a senior legal adviser at the European Union’s Court of Justice said Thursday that standard contracts for the transfer of personal data outside the bloc are in line with EU law on data protection.

But the opinion by Saugmandsgaard Øe, an advocate general at the EU court, also said that transfers to the U.S. under contractual clauses could be stopped if it was shown that the expected safeguards on adequate data protection were not respected.