not all of the Candidates take campaign donations from every Tom, Dick and Rupert that comes along, and they have to watch every expenditure.

To exclude a legal candidate from a debate, on the grounds of "how they choose to spend their campaign funds" is dishonest, pathetic, and about as "against the Constitution" as BushCO is.  

Which seems a bit arbitrary to me.

They should definitely let Dennis in the debate.  His views are a breath of fresh air, and as others have stated, are as truly progressive as you will find.

However, while Dennis has great principles and a great perseverence and sense of justice, he is not a good manager.  Until he becomes a better manager, he should not be President because he'll set back the progressive cause for years.