Are Democrats in trouble if Hillary's campaign collapses?

[Mister Mets]

A specific argument I've heard is that the lack of serious opposition for Hillary means that the Democratic party would be a in a very bad position if her campaign were to collapse for whatever reason.

You could argue that Hillary does have legitimate opposition. If the likes of Webb, O'Malley, Sanders and Chafee had challenged Gore, it would have been a big deal. Instead, Gore only faced Bill Bradley. But I get the counterpoint that an elderly man who had been one of the most conservative Democrats in the Senate, a failed Governor whose unpopularity gave him a Republican successor in Maryland, a 70-something socialist, and a former Republican officeholder whose stints as Senator and Governor ended unsuccessfully are not going to be Democratic nominees for President no matter what.

Hillary's advantages are so significant that the people who might win the nomination in a race without her aren't going to try. My guess had been that if something happens to Hillary, Democrats would just find someone else, so there'd be a functional nominee in 2016. As that individual wouldn't have a shot against Hillary, they're not going to bother now, since the only they'd win is if Hillary drops out.

On a 538 podcast there was a point that if Hillary exits the race, that's going to dominate political conversation for months, which could prevent a Cory Booker, Julian Castro, Amy Klobuchar, John Hickenlooper or Kirsten Gilibrand from being able to get their message out. Although that neglects the length of the primary process.

Now I'm conflicted. Does the lack of a credible opponent to Hillary Clinton mean Democrats are in trouble if she's unable to campaign? Or is it a moot point since they'd still have a credible nominee in 2016? There are also more nuanced answers. Does the lack of a credible alternative to Hillary mean weaker candidates (Biden, Cuomo, De Blasio) have a shot at the nomination without Hillary in the race?

[Mister Mets]

I find the argument that the Democratic bench is somehow empty sort of laughable. 44 Senators and 18 Governors and somehow the party has no one at all to recruit to run for President.

A party does only need one candidate on the top of the ticket.

Although there could be the argument that a rushed primary might allow a weaker candidate to be nominated.

[Mister Mets]

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Now I'm conflicted. Does the lack of a credible opponent to Hillary Clinton mean Democrats are in trouble if she's unable to campaign?…

Please present a list of all potential Republican and Democratic presidential candidates and tell us exactly how each one is or is not electable.

On the Democratic side, the only people (excluding unelected nobodies lucky enough to get on a ballot somewhere) running for President or hinting about running for President are Hillary Clinton, Martin O'Malley, Bernie Sanders, Jim Webb and Lincoln Chafee. And Clinton's the only one who could win a competitive presidential primary. So she doesn't really have a credible opponent in the primary.