CNN

Chris Dodd's campaign initiated the pledge that prevents campaign staff and out-of-state volunteers from caucusing.

DES MOINES, Iowa (CNN) –Democratic presidential candidate Chris Dodd's Iowa campaign announced today that with the addition of Illinois Sen. Barack Obama's campaign on Wednesday all the Democratic campaign offices in Iowa–except New Mexico Gov. Bill Richardson's–have signed on to a pledge asking the campaigns to prohibit their staff or out-of-state volunteers from caucusing.

Dodd's campaign said the point of the letter was to prevent campaigns from registering large amounts of staff — many of whom arrived in the state only months ago — from influencing the results of the caucus.

In a statement, the senator from Connecticut's Iowa state director Julie Andreeff Jensen said, “It’s still confusing and disappointing that the Richardson campaign has refused to join every other campaign in making this commitment. It’s troubling that I am forced to conclude that they are in fact intending to use paid staff to influence precinct caucuses.”

The Richardson campaign first refused to sign the pledge the same day it was created. State caucus director Shari Fitzgerald–a lifelong Iowan, according to the campaign–said, "I have participated in every Presidential caucus since 1972 and refuse to be bound not to caucus for the candidate of my choice by any candidate or their campaign–ever."

-CNN Iowa Producer Chris Welch