The conventional wisdom that it is almost impossible for a public figure to win a libel lawsuit has led some people to dismiss the possibility of Tulsi Gabbard suing Hillary Clinton over her comments about her.  I am not so sure.

Matt Margolis writes:

While it's easy to give Tulsi credit for taking a hard line against Hillary, this letter seems like a PR stunt to me. As a public figure, Tulsi should expect attacks and accusations, and threatening to sue over being called a bad word doesn't evoke a sense of toughness one needs to run for president.

YouTube screen grab.

As Margolis notes, even though she got a boost from Clinton's words, Gabbard's campaign has failed to take off.  But that is less of a reason to suspect she will give up on Mrs. Clinton's claims than to suspect she will press ahead.  Gabbard has a political future that could last decades, and she knows that the stain of the implication she is a "Russian asset" will never go away.  She is proud of her National Guard service overseas in combat zones.  And honor is a concept that means more in our armed services than in practically any other realm of modern life.  Gabbard's regard for her personal honor may be incomprehensible to many in modern America.

Gabbard and her organization must realize that Hillary Clinton does not handle apologies well.  In fact, I cannot recall a single actual apology from her in the nearly three decades I have followed her.  The closest I can recall is her referring to "shoulda, coulda, woulda" with regard to some mistake she made.  

The language her campaign is using in a letter to Clinton suggests an eye toward proving "actual malice," the legal standard that must be met for a public figure to succeed in a lawsuit.  Foreknowledge of the falseness of a claim along with animus toward the object of defamation must be proven.  Via Fox News:

Democratic presidential candidate Rep. Tulsi Gabbard of Hawaii is accusing former Secretary of State Hillary Clinton of defamation over a recent statement that implied Gabbard was a Russian asset and is demanding that Clinton issue a retraction.

A letter from the Gabbard campaign's legal counsel insisted that Gabbard is not a Russian asset, and that Clinton knew the statement was untrue when she said it.

"In making the statement, you knew it was false. Congresswoman Gabbard is not a Russian asset and is not being groomed by Russia," the letter said. "Besides your statement, no law enforcement or intelligence agencies have claimed, much less presented any evidence, that Congresswoman Gabbard is a Russian asset. This fabricated story is so facially improbable that it is actionable as defamation."

Here is what Hillary said in a podcast conversation with David Plouffe:

"I'm not making any predictions, but I think they've got their eye on somebody who is currently in the Democratic primary and are grooming her to be the third-party candidate. She's the favorite of the Russians. They have a bunch of sites and bots and other ways of supporting her so far. And, that's assuming Jill Stein will give it up, which she might not because she's also a Russian asset. Yeah, she's a Russian asset. I mean, totally."

There was then a slight backing away by Clinton's allies:

Early reports about Clinton's comments said that the former secretary of state meant that Gabbard was being groomed to be a third-party candidate by Russians, but it was later clarified that she was referring to Republicans. The Gabbard campaign counsel's letter accused Clinton of putting a "spin" on the statement to avoid liability.

"This Republicans-not-Russians spin developed only after you realized the defamatory nature of your statement, and therefore your legal liability, as well as the full extent of the public backlash against your statement," the letter said.

"Moreover, the Republicans-not-Russians spin cannot explain away your statement that Congresswoman Gabbard is 'a Russian asset,'" it continued. "That is, of course, because your Republicans-not-Russians spin is rubbish."

Gabbard's campaign is demanding a humiliating retraction:

The letter concluded by presenting a statement for Clinton to post on her Twitter account, and to send to major media outlets, apologizing. The proposed statement would say that she "was wrong," made a "grave mistake and error and judgment" and that she "support[s]" and "admire[s]" Gabbard's work.

The letter also demanded that Clinton "immediately" hold a press conference to make a verbal retraction of her past statement.

I don't think that will happen.  Maybe it is wishful thinking on my part, but because her campaign is not looking robust, Gabbard might use the necessity of defending her honor as a reason to end her presidential campaign and focus on pressing forward with litigation.  In a lawsuit for libel, there are opportunities for discovery on both the plaintiff and defense.  My guess is that Gabbard's communications with the Russians, if any, are blameless, and that she has little to fear.  Hillary, on the other hand, has a record of destroying 30,000-plus emails rather than turn them over to investigators.  In civil litigation, destruction of communications can allow adverse inferences to be made when pressing for damages, I believe.