Vice President Joe Biden isn't revealing his plans for 2016, but his campaign-style speech at Sen. Tom Harkin's annual steak fry in Iowa on Sunday set off a fresh wave of speculation that he wants to make a third bid for the White House.

Harkin's event has been a launching pad for Democratic presidential hopefuls ever since 1991, when Harkin used it to announce his own run for the presidency. The last time Biden spoke at the shindig was as a presidential candidate in 2007, although he went on to finish a distant fifth in Iowa's first-in-the-nation caucuses, behind Barack Obama and Hillary Clinton.

Biden appears to be a long shot, with a new CNN poll showing him with the support of just 10 percent of Democrats and left-leaning independents. Clinton, who hasn't said yet whether she'll run, is the runaway front-runner with 65 percent.

Biden's speech, however, offered some hints at how he might be planning to close the gap.

Chris Cillizza and Sean Sullivan note at The Washington Post that the vice president presented himself as the liberal voter's alternative to Clinton, talking up his record on two key issues important to the party's liberal base: He reminded the crowd that he had gone out on a limb and endorsed gay marriage (before Obama), and that he and Obama had made good on their promise to end the war in Iraq.

Here's Cillizza and Sullivan:

The message? I stood on principle. I led. And I did it on issues of massive importance to the party's liberal base...

[Biden] (and his political team) know well that when it comes to 2016, every single comment made by any Democrat looking at running will be viewed through the lens of former Secretary of State Hillary Clinton. And Biden knows well that the longtime knock against Clinton is that she is too political, too calculating — that she lacks a core set of principles that guide her public life. [Washington Post]

Underscoring the administration's track record in Iraq would have been more difficult if the White House had still been pleading for congressional authorization to fire missiles at Syria, to punish the government there for a deadly chemical weapons attack in August. Biden was able to focus on the importance of diplomacy, making the threat of another war in the Middle East seem "almost like a faded memory," says David Catanese at The Daily Beast.

The way voters [in Iowa] punished Clinton for her unapologetic support for the Iraq war five years ago must be etched into the vice president's mind. [Daily Beast]

Still, there isn't a lot of ideological daylight between Clinton and Biden; they both voted to authorize force in Iraq, while Clinton came out in support of gay marriage shortly after Biden did. Furthermore, the two politicians, by most accounts, are as personally close as colleagues can be in the cutthroat world of Washington.

Indeed, Amy Chozick at The New York Times this weekend reported that Biden may have an entirely different motivation for hinting at a run:

Mr. Biden, 70, is keenly sensitive to perceptions about his political stature, and he is sending signals that he wants to be taken seriously in the 2016 conversation. He also wants to maintain maximum leverage within the Democratic establishment, especially with the Clintons, three people close to him said.

"Joe always says, 'If you're not on your way up, you're on your way down,' " one of the people said. A former administration official aide agreed, saying, "He needs to make people think he has skin in the game in the future so that they treat him relevant now." [The New York Times]