THE United States will join a New Zealand-led global campaign to stamp out violent extremism online, the White House said, making a policy change two years after the administration of former President Donald Trump declined to participate. The initiative was started by New Zealand Prime Minister Jacinda Ardern and French President Emmanuel Macron in 2019 after a gunman killed 51 people at two mosques in the New Zealand city of Christchurch while live-streaming his rampage on Facebook. Biden administration spokeswoman Jen Psaki said the United States would join the "Christchurch Call to Action to Eliminate Terrorist and Violent Extremist Content…