Should the word following a colon or dash be capitalized?

Words following a colon are often capitalized, while words following a dash are normally not capitalized. However, full sentences or long quotations following a colon or dash generally begin with a capital letter:

Harry Truman stated:  "The buck stops here."

Our goal is  clear:  The Board's action must be implemented.
or
Our goal is clear‚the Board's action must be implemented.