Curate, connect, and discover
America's modern psychic shields are Magnus's Numinous tech, which implies that they didn't have shielding prior to Magnus's rightward shift and his involvement with America. So when then, did Etienne not stop the New Mexico Festival Massacre, or at least warn Valentina? Was it a deliberate attempt to alienate her from America? Or was he even hoping that they would succeed? The balancing act would be easier with one less Superpower around, even if its Valentina, but I think they're were still too close at that point for Etienne to do that.
And more importantly, how did he explain this lapse to Valentina?