As fears mount over Tehran's involvement in the Israel-Gaza conflict, the Biden administration has sent a clear message to Iran's regime: exercise caution. A spokesman for Hamas had told the BBC that it had received support from its ally Iran for the unprecedented attacks against Israeli civilians. And another report in the Wall Street Journal quoted unnamed members of Hamas and the Lebanese guerilla movement Hezbollah as saying that Iran gave the go-ahead for the attack more than a week ago. While Iran's leaders have celebrated and praised the attacks on Israeli citizens, Iran's Foreign Ministry has downplayed its role,...