Spiro Agnew, Not Much Heft?

Spiro Agnew had only been Governor of Maryland for two years when picked by Richard Nixon to be his VP pick.  Agnew had, as County Commissioner for Baltimore County, he was among the first people in the nation to sign a bill preventing "whites only" businesses.

Agnew was involved in national politics in the 1950s, many times working (at what level?) the House campaign of James Deveraux.