Under President Ursula von der Leyen, the European Commission wants to make EU security less dependent on Washington by pooling data and analysis from national agencies. But the idea is already causing unease in some capitals where governments fear sharing secrets across borders—especially with pro-Russian voices growing louder in Budapest. The debate gained new urgency after President Donald Trump hinted the U.S. could dial back its support for Europe and briefly paused intelligence sharing with Ukraine earlier this year.