http://online.wsj.com/article/SB121969145343270091.html
Walk into almost any hotel here this week and you can find an odd sight: Liberal Democrats starting their day by lobbying moderate and conservative Democrats.
The lobbyists are members of the Progressive Democrats of America, an activist group working to keep the party true to liberal priorities, and they have been assigned to every hotel housing Democratic convention delegates.
"At breakfast, where they go to get their talking points , we will be there," says Tim Carpenter, a veteran of Democratic campaigns and national director of the PDA.
The fact that Mr. Carpenter and his cohorts feel compelled to buttonhole other Democrats to push a liberal agenda is a sign of a quiet tension lurking within the Democratic Party. That tension is a potential complication for Sen. Barack Obama now, and it is certain to be one for him and his party if he is elected president.