2) Nominating someone with Sanders' profile would be a clear risk.

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The first point is not terribly controversial. Sanders won the popular vote in Iowa (although he was edged out by former South Bend, Indiana, Mayor Pete Buttigieg), won the New Hampshire primary and crushed the competition in the Nevada caucuses by, among other things, winning a majority of the Latino vote. Polling in the run-up to the South Carolina primary on Saturday suggests Sanders is in second and within striking range of former Vice President Joe Biden. Sanders is also well-positioned to run well in major delegate hauls in California and Texas on Super Tuesday.

The second point is waaaaay more controversial. Sanders and his campaign reject the idea that he is a risk at all, arguing that the biggest risk of all would be nominating another status quo pol who can't expand the electorate to new (and young) voters like the Vermont senator can.

Which may well be true! But objectively there is clear evidence that picking a nominee with Sanders' profile -- a 78-year-old self-avowed democratic socialist -- is, in fact, a risk.

Every year -- dating back to 1937(!) -- Gallup asks voters a series of questions about whether they would be willing to vote for someone with certain attributes. Like, would you vote for a woman for president? (93% of Gallup's 2020 sample said they would.) Or would you vote for a gay/lesbian candidate? (78% said they would.)

Of the four candidate traits that were seen as the least appealing (or the most likely to cause a pause in voting for a candidate), two are directly relevant to a Sanders candidacy. Less than 7 in 10 (69%) said they would be willing to vote for a candidate over 70, while less than half (45%) said they would back a candidate who was a socialist. The only other candidate traits that rated so poorly were a Muslim candidate (66% would support) and an atheist candidate (60% would support).

Let's take them one by one.

1. Age:

At 78, Sanders isn't the only septuagenarian in the race. Former New York City Michael Bloomberg is 78. Former Vice President Joe Biden is 77. Massachusetts Sen. Elizabeth Warren is 70. But judging by the Gallup numbers, nominating any one of those candidates would amount to a risk -- given that roughly 3 in 10 people were willing to tell a pollster they wouldn't vote for someone that old.

(Sidebar: You should assume the actual number on all of these questions is slightly lower given that people may not want to be totally candid about who they won't vote for -- and why.)

So if you are 70+ and running for the Democratic nomination, it is fair to describe it as a risk for voters to nominate you. A manageable risk perhaps. But a risk nonetheless!

2. 'Socialist':

When you look at the numbers for a "socialist" candidate, you start to see why Sanders' positioning could be much more problematic in a general election than a Democratic primary. Among self-identified Democrats, more than 3 in 4 (76%) say they'd be willing to vote for a socialist for president. But that number dips to 45% among independents and just 17% of Republicans. Which would suggest that disgruntled Republicans looking for someone other than President Donald Trump to vote for would not find it in a socialist nominee.

But Sanders isn't a socialist, you argue! He's a democratic socialist. Totally different!

Here's how Sanders explained his views in a "60 Minutes" interview last Sunday with Anderson Cooper:

"When Donald Trump was a private businessman in New York, he got $800 million in tax breaks and subsidies to build luxury housing. That's called corporate socialism. What democratic socialism is about is saying, 'Let's use the federal government to protect the interests of working families.' "

Ask yourself whether you think that the average voter will make that distinction -- particularly in the course of a deeply heated and nasty campaign? And then consider what several of Sanders' fellow Democrats said about his party affiliation during Tuesday's debate.

"I am the only one in the New Hampshire debate when asked if we had a problem with a socialist leading the ticket that raised my hands," said Minnesota Sen. Amy Klobuchar. "I like Bernie. We came in together to the Senate. But I do not think that this is the best person to lead the ticket."

"I am not looking forward to a scenario where it comes down to Donald Trump with his nostalgia for the social order of the '50s and Bernie Sanders with a nostalgia for the revolution politics of the '60s," Buttigieg said. "This is not about what was happening in the '70s or '80s, this is about the future."

If that's what Democrats are saying, imagine what Republicans will say. Actually, you don't have to imagine! Here's House Majority Whip Steve Scalise on Wednesday : "It's unfortunate when you see what's happening on the Democrat side, that their party's been taken over by socialism."

Now. None of the above means Sanders can't win. Being a risk and being a loser are two totally different things. After all, there was NO more risky nominee for Republicans in 2016 than Trump -- and look where he wound up.

All the above does prove is that based on voter sentiments about who they would and would not vote for, choosing Sanders as the Democratic nominee does pose a real risk. How much of one? And is it a risk Democrats should be willing to take? We won't know the answer to that until this fall.