Can you get trademark protection for a very simple slogan like 'Support This Cause' if the cause itself is public and very general?

It is not very likely based on what can be found reading ''Chapter 1200: Substantive Examination of Applications'' of the ''Trademark Manual of Examination Procedures (TMEP) - 4th Edition'' published by the United States Patent and Trademark Office; more specifically Section 1202.03(f)(i) Slogans or Words Used on the Goods, and Section 1202.04 Informational Matter.