Vice President Joe Biden speaks at George Washington University April 28, 2014, in Washington, D.C.

Joe Biden Heading to Netroots Nation

2 of the 3 biggest stars in the Democratic Party are heading to the liberal gala.

Vice President Joe Biden speaks at George Washington University April 28, 2014, in Washington, D.C.

Vice President Joe Biden is slated to speak on June 17 at Netroots Nation in Detroit. 

By + More

The announcement Wednesday that Vice President Joe Biden is heading to Netroots Nation means that two of the three biggest stars in the Democratic Party will attend the largest gala of progressives in the nation this year.

Hillary Clinton, meanwhile, will have a bus visiting in her absence.

Biden will join Sen. Elizabeth Warren, D-Mass., during the three-day conference in Detroit, Michigan. He’s scheduled to speak a week from Thursday; Warren is slated for a morning address the day after. That same weekend Clinton will be doing a book signing in St. Paul, Minnesota, about a 90-minute flight from Detroit.

[READ: Hillary's Favorability Drops Under 50 Percent]

It will mark the first time Biden’s talking at the conference and will come at point when the Democratic Party is wrestling with how best to approach the issue of income inequality.

“From his longtime support of labor unions to speaking out on important issues like LGBT equality, Vice President Biden has in many ways given heart and soul to this administration," said Raven Brooks, executive director of Netroots Nation, in a statement.

Clinton, in the midst of a monthlong promotional tour of her book, declined an invite. In one sense, it makes sense for her to avoid the risk of a cool welcome by some of the nation’s most hardened liberals. But if The New Republic’s Noam Scheiber is right, she’s already made great inroads with the group who torpedoed her nomination six years ago.

[ALSO: Why Republicans Picked Cleveland]

Now that two of the Democrat’s top three potential 2016 presidential candidates will be present, Clinton’s absence will only be amplified.

But she’ll have a surrogate of sorts on her behalf. Ready For Hillary, a pro-Clinton group unaffiliated with the former Secretary of State, is sending its bus to the conference.

Whether attendees are ready to hop on will be a fair measure of how far Clinton has come with the left.