"If we can't get the platform planks that the Senator supports in the platform during the committee process, if we can't get the electoral reform that the Senator is advocating, then of course those things would have to go to the floor for voters during the convention," Jeff Weaver said Tuesday on CNN's "New Day."
Weaver told CNN's Alisyn Camerota there's no concern that Sanders supporters will misinterpret "get messy" as advocating aggression; they know that it means heated debate.
"We're just going to have votes on the floor of the convention. That's all. There will be debate and there will be votes," he said. "You don't often see that anymore in modern conventions. But in fact, that's what conventions are really about -- for parties to do the business of the party."
the Associated Press in a report published Monday that the convention could be "messy" if party leaders do not adopt a progressive agenda.
"Democracy is not always nice and quiet and gentle but that is where the Democratic Party should go," Sanders said.
"Democracy is messy. Everyday my life is messy. But if you want everything to be quiet and orderly and allow, you know, just things to proceed without vigorous debate, that is not what democracy is about," he added.
Sanders stood by his description Tuesday on NBC's "Today," saying the media often takes his words "out of context."
"The context of that was that democracy is messy, that people will have vigorous debate on the issues," he said.
"Of course it will be, but everything -- that's what democracy is about," Sanders added.
Hillary Clinton campaign spokesman Brian Fallon said he doubts that the convention will be messy because he believes Democrats will ultimately unite against Republican presumptive nominee Donald Trump.
"Given the relative lack of difference on policy that we have compared to Republicans, I think this process will be a lot less messy than a lot of people are suggesting," he said on CNN's "New Day" Tuesday.