With the 17-person all-out battle for the Republican nomination capturing most of the political spotlight, Democrats remain unsure about whether vice president Joe Biden should expand the Democratic pool to 6 candidates.

In a new Gallup poll conducted last week, Democrats were split by Biden's entry to the race, but seem to have resigned themselves to the fact that Elizabeth Warren won't.

Biden is now sitting on a six-year high in popularity among all voters, but has astonishing popularity among Democrats, with 3 out of 4 finding him favorable.

So what's holding Democratic voters back?

Almost certainly, some of it is a fear of succumbing to a free-for-all Democratic version of the Republican race. In 2008, the Democrats benefited from the extended press coverage in the primary battle between Hillary Clinton and President Obama, but the party seems more interested in finding a decisive victor.

Former Governor Martin O'Malley's campaign has complained that the Democratic debate structure is rigging the election for Hillary Clinton--and claiming that the DNC is violating federal election laws by doing so.

Whether or not O'Malley is correct, it does seem like the Democratic Party is trying to limit the debate, if for no other reason than to avoid some of the embarrassment and bruising the Republicans are facing.

A Biden candidacy might fall victim to Obama's 2008 strategy -- i.e. Republicans will say a Biden presidency will only be 4 more years of Obama. While this should be a concern, the top two contenders, Clinton and Bernie Sanders, both have more than enough political baggage themselves.

Simply put, the democratic nominee will face incredible mud-slinging.

At 72, Biden would be the oldest president elected (Hillary would be the second oldest. Sanders would be the oldest). This has been a growing trend in American politics as the population ages with advances in gerontology -- but it could still be a political thorn.

In any race of an older candidate versus a younger one, about one-third of the voters historically consider age to be a critical factor. This could be a serious factor in 2016--with the vast majority of the Republican candidates under 65.

Potentially as the oldest candidate, Biden still has a political toughness, one that other Democrats are not really showing. Biden's role as vice-president was the traditional attack dog, and he plays the role well when defending policy and campaigning.

Vice president "potty-mouth," known for well-timed expletives, could be just what the Democrats need to combat Republican front-runner Donald Trump's say-anything strategy.

While it is still uncertain if Biden will join the race, if he does, his democratic opponents will have to sharpen their game, and transition from chipping away at the Republicans to focusing on winning the primary.