I came back from a few days away to a barrage of emails from supporters of Sen. Bernie Sanders, who is campaigning for the Democratic presidential nomination. Many emailers cut and pasted this message, part of this Reddit thread, which objected to Monday's Morning Edition conversation between political analyst Cokie Roberts and host Renee Montagne.

The segment, which was pegged to questions about whether Vice President Joe Biden would enter the race, was headlined "Will Another Democrat Make A Bid For The Presidency?" The complaint says the piece "implies not only that there is currently no Democrat offering a serious challenge to Clinton for the 2016 presidential nomination, but that if there was to be one, it would be Joe Biden. Both of these points are incorrect-there IS a challenger to Clinton already, and it is Senator Bernie Sanders."

I asked Morning Edition executive producer Tracy Wahl about the segment. "We do lots of conversations where we talk about candidates and not all of them are about the field," she said, adding, "This conversation in particular was really about Biden. We wouldn't want to go through the whole list every time we mention one candidate." That particularly holds true on the Republican side, she said, where there are 17 declared candidates with national standing. "If we mentioned one Republican candidate we just couldn't mention them all."

The piece was framed by the introduction from Montagne, who said "And on the Democratic side of the presidential race, presumed front-runner Hillary Clinton is running into some headwinds." Later, Roberts talked about other developments in the Clinton campaign, including new ads.

It would have been easy enough to slip in a few words about the other Democratic candidates; unlike on the Republican side there are only four other declared Democratic candidates with national standing, including Sanders. But the piece did not say Clinton had no other opponents nor did it imply that, at least in my reading of it.

Many listeners and readers who wrote added that they feel NPR has ignored Sanders' campaign, or framed it largely as a counterpoint to that of front-runner Clinton. I've been getting variations of that complaint since even before Sanders launched his bid for the nomination. I've already written about what I thought was NPR's overuse of the label "long-shot" to describe Sanders early on and an unfortunate exchange between Sanders and Diane Rehm, host of an NPR-distributed program.

But as I've written back to Sanders supporters who feel their candidate is getting short shrift, I don't find that NPR has been slighting his campaign. In the last two days alone, NPR has covered the Democrats' climate change stances and reactions to the Republican debate and Sanders has been well in the mix.

NPR has aired or published several stories that did indeed look at Sanders in relation to Clinton, such as this somewhat dismissive one (from the very savvy Ron Elving, who may be entirely right in his assessment of the final outcome), and many others that did not, including a piece on his small donor-fueled fundraising, one on the large crowds he is drawing and this wide-ranging interview.

This campaign season, with more than 20 declared candidates so far, is already an unusual one, and the upshot seems to be that not every story may get told with the timeliness or thoroughness that every candidate's supporter would like to see. But with nearly six months before the Iowa caucuses and the New Hampshire primary kick off the nominating process, there is still plenty of time for detailed reporting about each of the candidates.

Updated Aug. 12 at 1:45 p.m. ET

Many Sanders supporters have emailed about the statistics posted by "Sesto" in the comments thread below (and also posted on Reddit.) As I noted in the comments, NPR does not have "candidate pages" so it's unclear where some of those numbers came from. In addition, the tagging of stories on NPR.org is not a reliable measure of coverage.

My office ran its own numbers, for the dates April 28 (when Vermont Public Radio first reported Sanders planned to make a formal announcement about running) through Aug. 10. We looked at broadcast-only stories that mentioned Sanders and/or Clinton and ran on the weekday and weekend morning and evening newsmagazines and the weekday afternoon program "Here and Now," which is produced by NPR and Boston station WBUR.

Clinton was mentioned 125 times during that time. Sanders was mentioned 46 times. Thirty-nine of the stories included in those figures mentioned both candidates. Seven stories mentioned Sanders and not Clinton. Of the 86 stories that mentioned Clinton but not Sanders, 72 were directly related to her campaign; the rest (14) covered topics related to her past work as secretary of state, or other topics not specifically about the presidential campaign. Among the 86 stories that mentioned Clinton but not Sanders, 30 were primarily about Republican candidates and Clinton's name came up (raised by the candidates or NPR) because Clinton is the front-running Democratic candidate.

By comparison, Martin O'Malley, Jim Webb and Lincoln Chafee--who all jumped into the campaign for the Democratic nomination much later than Sanders and Clinton and are running well behind them in the polls—have gotten far less attention from NPR. During the same time frame, O'Malley has been mentioned 18 times on air, Webb has been mentioned three times and Chafee twice.

I circulated the Clinton/Sanders numbers in the NPR newsroom. Shirley Henry, deputy Washington editor, and Domenico Montanaro, supervising editor for politics and the lead political editor, sent me the following statement:

Hillary Clinton has been a national political figure for more than two decades, was a prominent cabinet member in the Obama administration, and has been the far-and-away leading contender for the Democratic nomination for much of this year – and fundraising, campaign infrastructure and polling have borne that out. She is also named on many occasions by Republican candidates and has been targeted by the Republican Party itself long before she even got in the race. Because of those factors, she has expectedly been the subject of more news reports than Sen. Senders.But Sen. Sanders clearly has a deep following and has come on as a serious candidate. NPR has done perhaps the most in-depth profile any news outlet has run about him, has gotten out on the campaign trail with him and reported on some of his large crowds. We fully intend to continue to follow him and to get out on the trail with him again as news warrants in this young campaign season.As to the numbers of how many stories or mentions there have been of Sen. Sanders, we certainly try to be cognizant of some balance between candidates. However, the numbers are not exactly an apples-to-apples comparison and not all stories are created equal. The metrics don't reveal the quality – or breadth – of the reports NPR has done. There are a lot of candidates running for president – on both sides. Over time, NPR will do its best to get to as many as we can, if not all, in a comprehensive way and provide the depth and context our listeners expect.

A couple other points from me: Many have contacted my office about NPR's reporting about the crowds attending Sanders' recent events. NPR has indeed reported on them repeatedly in hourly newscasts in recent days, as well as in Cokie Roberts' Morning Edition analysis.

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