For much of its seven-year existence, the Black Lives Matter movement has been seen by many Americans as a divisive, even radical force. But suddenly it’s gone mainstream. In the wake of George Floyd’s death, Republican Sen. Mitt Romney joined a Black Lives Matter march. Some NASCAR drivers have embraced the phrase. So has NFL Commissioner Roger Goodell. Many black activists welcome the developments but worry that businesses and politicians will hijack the slogan without any real commitment to doing the hard work needed to fight racism.