Complex sentence: Smoot was running for the U.S. Senate at the time, but LDS president Snow favored Thomas Kearns and Smoot became insignificant to Clark and faded from the SP, LA & SL corporate roster.
Split into simpler sentences: Smoot was running for the U.S. Senate at the time, but LDS president Snow favored Thomas Kearns. Smoot soon became insignificant to Clark and faded from the SP, LA & SL corporate roster.