With all the recent announcements, it appears that at least 20 Democrats and Republicans will be running for president in 2016. The field is so crowded that, at first glance, it's a mystery that some of them aren't running as independents. After all, some Republicans, like Sen. Rand Paul, don't seem to fit their party's mold, and Sen. Bernie Sanders of Vermont and former Gov. Lincoln Chafee of Rhode Island both won office as independents but are running as Democrats.

The answer to the mystery may be simple. If you are an independent, you have no chance of participating in the final fall 2016 presidential debates, and if you aren't in the debates you can't become president. Why can't an independent stand on the stage with the Democratic and Republican nominees? Because rules set by a commission dominated by the two major parties stand in the way.

For the men and women who run for president and vice president of the United States, the national debates are a great rite of passage in the long political campaign. Every four years, tens of millions of Americans watch the nominees make their case to the voters in the final weeks before Election Day. Some voters decide who "wins" each debate; others use the debates as the means to decide for whom to vote. 

I understand the power of the debates. I had the great honor of standing on that stage in 2000 as the Democratic Party's vice presidential nominee.

ADRIANA SCOTT FOR USNWR

That is why I am deeply concerned about a rule that was established 15 years ago that serves only the Democratic and Republican nominees and blocks third-party candidates from participating in the presidential debates. A rule that has the effect of excluding independents is unfair and harmful to our democracy.

Since 1960 (when the debates began) only candidates who ran in a Democratic or Republican primary would have qualified for the debates under the current rule. That means any independent who chose to run outside the two major parties – like Ross Perot, who qualified for the debates in 1992 – would not qualify today under the current rule.

This rule would be unfair at any time, but it is especially undemocratic at a time when the polls show that the American people have become increasingly alienated from the two major parties. More than 43 percent of Americans today identify as politically independent – a higher number than ever before – and 76 percent believe it is important to elect independents to break the partisan gridlock in Washington. Younger voters in particular do not feel anywhere near the kind of attachment to the Republican or Democratic parties their parents or grandparents did.

The public has become alienated by the two major parties because they are too often captured by the forces of ideology or partisanship, which is especially evident during the primary process. I experienced this in the state of Connecticut when I ran for re-election to the Senate as a Democrat in 2006. Although I was defeated in the Democratic primaries, I was able to win re-election because the majority of Connecticut voters, including Democrats, were good enough to support my candidacy as an independent in the November election.

The public must have the option of voting for viable independent candidates when the two major parties no longer reflect or address their views. But the Commission on Presidential Debates – the little known but powerful organization in Washington that establishes the debate rules – is denying the public this right at the presidential level.

The CPD's current rule requires an independent candidate to exceed 15 percent in the polls two weeks before the Presidential debates. No independent has ever qualified for the debates under this rule because of its timing and its threshold. Remember that an independent candidate does not benefit from the wall-to-wall media coverage that the Republican and Democratic candidates receive through participating in their party primaries. This media coverage has enabled relatively unknown Republicans or Democrats to become nationally known names.

Without this media coverage an independent is forced to raise and spend exorbitant sums of money to gain the necessary name recognition among voters. There are many great Americans who might consider running for president if the rules gave them a fair shot, but who would run as an independent when our electoral process is blocked by these kinds of unfair obstacles?

In short, the two major parties – through the Commission on Presidential Debates – have concocted a rule that makes it almost impossible for independent candidates to run successfully for president. That is wrong, and it is contrary to the clearly expressed interests of the American people. That's why I have joined with dozens of other policymakers, politicians, military leaders, diplomats and academics to challenge the Commission on Presidential Debates to break the stranglehold the two parties have on our presidential elections and establish rules that allow for an independent candidate in the debates.

We believe it is essential that a new rule enable an independent candidate to qualify for the debates by April 30^th so the candidate has at least six months to garner the media attention and name recognition necessary to compete on a level playing field with the Democratic and Republican nominees. We also believe there are ways to open up the process so that all independent candidates can compete for a third slot in the debates. A third slot will broaden the debates beyond the two major parties but not make the debates chaotic because of too many candidates participating.

It has been 23 years since we last saw an independent candidate on the presidential debate stage. Under the current rule we may never see another one. The American people are demanding more competitive and inclusive elections, and they want independents to have a fair chance. The Commission on Presidential Debates should live up to its responsibility and change the rule now.