Dictionary.com Unabridged (v 1.1) - Cite This Source fifth column
–noun 1. a group of people who act traitorously and subversively out of a secret sympathy with an enemy of their country.
2. (originally) Franco sympathizers in Madrid during the Spanish Civil War: so called in allusion to a statement in 1936 that the insurgents had four columns marching on Madrid and a fifth column of sympathizers in the city ready to rise and betray it.
Morris is a pollseter, and a political consultant. If Bill believes in governing by polls, Morris supports him in that completely.
Morris knows how many people are deeply entrenched in their dislike of Hillary and that he is in a unique position to exploit that.
He has also shown himself to be rather lacking in the honorable traits, so I don't see him having a lot of qualms in working both sides here. He makes his living from one side, but maintains access (and who knows what other goodies) from the other side.
In a match-up between him and the Clintons, singularly or jointly, who do you think would be the better manipulator??