Complex sentence: Such talk began before he even took office, but the efforts gained in potential seriousness following a series of developments and revelations during May 2017, but so far there is no broad-based movement towards such a measure.
Split into simpler sentences: Such talk began before he even took office, but the efforts gained in potential seriousness following a series of developments and revelations during May 2017. So far, however, there is no broad-based movement towards such a measure.