Complex sentence: With his visa finally approved, Browder's newsletter was abruptly terminated at the end of April 1946 and the former American party leader immediately departed for the Soviet Union to determine whether his expulsion could be overturned.
Split into simpler sentences: With his visa finally approved, Browder ended publication of his newsletter at the end of April 1946. The former American party leader departed for the Soviet Union to determine whether his expulsion could be overturned.