Mysterious outside groups are asking state parties for personal data on potential delegates, Republican campaigns are drawing up plans to send loyal representatives to obscure local conventions, and party officials are dusting off rule books to brush up on a process that hasn’t mattered for decades.

As Donald Trump and Ted Cruz divide up the first primaries and center-right Republicans tear one another apart in a race to be the mainstream alternative, Republicans are waging a shadow primary for control of delegates in anticipation of what one senior party official called “the white whale of politics”: a contested national convention.

The endgame for the most sophisticated campaigns is an inconclusive first ballot leading to a free-for-all power struggle on the floor in Cleveland.

“This is going to be a convention like I’ve never seen in my lifetime,” said veteran operative Barry Bennett, who managed Ben Carson’s campaign until December and is now advising Donald Trump. “It’s going to be contentious from Day One.”

more: http://www.politico.com/story/2016/02/brokered-republican-convention-cleveland-219306