Well, let me take a few minutes to debunk both claims, starting with the head-to-head matchups. There are two important things that Bernie supporters are missing here: the first is that head-to-head matchups in May are not indicative of the way a general election is likely to turn out. If memory serves, Clinton was polling better against GOP nominee John McCain than Barack Obama in May of '08. We all know what happened. Obama went on to win a landslide victory over McCain. As I've said on more than one occasion, we won't get a handle on who is the favorite in this horse race until September.
The second thing Bernie supporters are missing regarding poll numbers is that their candidate, for the most part, has had a free pass regarding negative ads, while Clinton has been the political equivalent of a piñata. From the time she stepped down as Secretary of State, she was in the crosshairs of the GOP attack dogs. Sadly, many of Bernie supporters have been repeating, almost verbatim, Republican talking points on her. Were Sanders to actually win the nomination, all that attention would move in his direction. They would throw the kitchen sink at him, just like they've been doing with Hillary. Under that intense scrutiny, I seriously doubt Sanders would be polling as well as he is currently doing, especially with his policy positions. In no time at all, the GOP would have a majority of Americans believing Bernie was a distant cousin of Karl Marx.
Now let's talk about that second claim about the independent vote. It seems all we keep hearing about these days is how the independent vote is crucial to determining who wins the White House. Funny thing about that stat: it actually isn't true. For instance, in 2008, Obama won the independent vote and obviously won the election; but in 2012, he lost the independent vote, yet still beat Mitt Romney by five million votes. Ironically, the only swing state that Obama got the majority of the independent vote that year was North Carolina, which he lost.
So why the discrepancy? I think it comes down to one simple fact. The term independent has changed dramatically over the last twenty or so years. There was a time when independent voters were just that: independent. They did not affiliate themselves with either major party, nor did they want to. They were, for lack of a better word, moderates or centrists. They were called Reagan Democrats in the '80s and Clinton Republicans in the '90s. True swing voters. But they were, ostensibly, the same voting bloc.
That is NOT the case today. Many of today's independent voters are far more ideological in their political leanings, and break down along two very distinct categories. One is progressive; the other conservative. For these voters, the major political parties are seen not only as part of a corrupt and rigged system, but as betraying the values they hold near and dear. Progressive independents think the Democratic Party isn't progressive enough; conservative independents think the Republican Party isn't conservative enough. Far from being moderates or centrists, these voters represent the extreme flanks of the political spectrum and they have been engaged like never before by the candidacies of Sanders and Trump, both of whom have given them something to rally around.
A piece by Nate Silver of fivethirtyeight.com corroborates this. In it, Silver writes,
It's critical not to confuse "independents" with "moderates." Sanders's career itself underscores that point: He long called himself an independent, even while compiling a very liberal voting record. Sanders has demonstrated a real outside appeal that does better among people with a similar profile, people who lean left but are wary of calling themselves Democrats. We should also avoid reading too much into Sanders's support among independent leaners in terms of how he'd fare in November: The independents who vote in party primaries are in no way representative of independents generally.Now don't get me wrong, I'm not saying that Hillary Clinton doesn't need to make inroads with Bernie supporters; she does. What I am saying is that this particular group of voters on the left - as well as Trump's core group on the right - are not, by any stretch of the imagination, what we would typically refer to as traditional independents. It's unclear just what percentage of the overall electorate they make up. But to make the claim, as the Sanders campaign has, that winning the independent vote is the key to defeating Trump in the fall, is factually inaccurate.
There are two reasons I know this. The first is, even with Sanders taking the lion's share of the independent vote, Clinton is still either within the margin of error or flat-out leading in the polls. If there was any truth to the Sanders' claim, she would be trailing, and trailing badly. Secondly, Trump himself is now pivoting over to the middle in order to snatch up the real independent / moderate voters, a sure fire sign that his campaign knows it will need to win the center in order to win the White House.
If someone as detached from reality as Trump can figure out that you can only go so far with just the support of your base, one has to wonder what is going on over in Bernieland.