In an email from March, an advisor to the Clinton campaign warned that Hillary Clinton should stop lying about her rival, Senator Bernie Sanders. The email, released by WikiLeaks in “The Podesta Emails” (a compilation of Internet records involving Clinton campaign chairman John Podesta), warned that if Clinton kept misrepresenting Sanders, she would risk losing his supporters in November.

Brent J. Budowsky, a former congressional staffer and current liberal blogger who has written for The Hill, the LA Progressive, and The Huffington Post, suggested that Sanders should team up with Massachusetts Senator Elizabeth Warren and New York Mayor Bill de Blasio to raise money for Clinton’s campaign in November. Then comes this bombshell:

Beyond this Hillary should stop attacking Bernie, especially when she says things that are untrue, which candidly she often does. I am one of the people with credibility to suggest Bernie people support her in November, and she and Benenson and others have no idea of the damage she does to herself with these attacks, which she does not gain by making.

Budowsky wanted to urge the Bernie Bros to declare, “I’m with her,” but he feared — rightly — that if Clinton kept attacking Sanders, she might lose some of his supporters.

Next Page: A look at Clinton’s opposition research against Sanders.

Indeed, among the emails is a list of opposition research on Sanders compiled by the Clinton campaign. Some of the attacks are disingenuous — Clinton prepares to blast her opponent on dismissing gay marriage at a time when she opposed it, and she plans to attack him for supporting a bill that her husband signed into law.

*LGBT (Marriage & Civil Unions) – *Sen. Sanders is attacking Secretary Clinton, claiming she has been inconsistent and late to supporting marriage equality. But Sanders is rewriting history on his own record. In 2000, Sanders was reluctant to take a clear stand on civil unions and marriage equality, and did not speak out forcefully on the issue. Sanders called for an end to the divisiveness of the opposition, saying there were “a dozen other issues out there that are as important or more important as that issue.” While other Vermont politicians were moving forward the cause, Sanders remained relatively quiet. Moreover, his oft-touted opposition to the Defense of Marriage Act omits Sanders’s reasoning: he thought DOMA injected the federal government into a states issue. *Nuclear Energy – *Sanders voted for a waste removal compact that moved radioactive waste from Maine and Vermont to a dump site near a tiny community in Sierra Blanca, Texas. Sanders said the compact was “good environmental policy” and said he was “in strong support of the bill.” Critics of the deal said that the site was not only environmentally unsound, but also near a small community that was low income and largely Hispanic. The compact was opposed by LULAC and the NAACP, and a local opponent to the deal called it “environmental racism.” NOTE: President Clinton signed the bill in 1997.

She also attacked Sanders’ record on unions, suggesting he was bought off by the sugar industry.

*Labor/Pay to Play/Sugar – *Sanders, often thought of as a champion of labor unions, accepted support from a company while it was involved in a bitter labor dispute—locking out union employees for nearly 22 months. In July 2012, he accepted $10,000 in contributions from American Crystal Sugar, while the workers had been locked out for nearly a year due to failed labor negotiations. The workers’ union widely opposed the company’s contract proposal because it could have doubled their out-of-pocket health care costs. At the same time American Crystal Sugar was proposing to cut back on workers’ health benefits, it spent more than $2 million in lobbying money and campaign contributions to politicians like Sanders in order to preserve its favorable sugar commodity program. Sanders voted to protect the sugar program.

Sanders’ supporters have every right to be angry, and should seriously consider voting for Libertarian nominee Gary Johnson or Green Party nominee Jill Stein in November.