End Is Near For Much Of Democratic Field

Twenty Democratic presidential candidates will debate Tuesday and Wednesday night. It will be the last time voters will see some of them on a debate stage.

The Democratic National Committee's rules for inclusion in early debates -- the first from NBC in late June in Miami, and the second from CNN this week in Detroit -- were quite generous. If Sen. Michael Bennet -- currently polling at 0.2 percent in the RealClearPolitics average of national polls -- got in both, then it's safe to say the rules were not terribly restrictive.

But that's over after Detroit. Party rules call for new qualification standards for candidates in the next debate, scheduled for September in Houston. Candidates will be required to meet a new polling standard and a new donations standard.

To make it onstage, candidates will have to "receive two percent or more support in at least four polls (which may be national polls, or polls in Iowa, New Hampshire, South Carolina, and/or Nevada)," according to the DNC. The committee went on to list several specifications for the polls themselves to make sure the candidates can cite support in legitimate surveys.

Beyond that, the DNC says, candidates must show they have received donations from at least 130,000 unique donors, plus at least 400 unique donors in at least 20 states. Together, those rules will eliminate a lot of current Democratic candidates.