Throughout the Democratic Primary, populist firebrand and progressive icon Senator Elizabeth Warren stayed completely neutral, neither endorsing Bernie Sanders nor Hillary Clinton   even after the Massachusetts primary.After Clinton clinched the nomination on June 7 after securing the amount of pledged delegates, sources close to Warren and Clinton told Reuters that the Massachusetts Senator will be making an endorsement   and she will be endorsing the presumptive nominee Hillary Clinton.As Sanders heads to Washington D.C. on Thursday to talk with President Obama and Senate Majority Leader Harry Reid, Warren s move could be seen as a bridge to unity, due to the fact that sources close to the senator say she is not ruling out a vice presidential position.Warren, who has made national headlines over the last few months taking on the thin-skinned GOP nominee Donald Trump, told sources the announcement would come  soon,  in about a week or two.A Clinton /Warren ticket would help unify the Democratic Party, bringing together Clinton s moderate-to-progressive base with Sanders  idealistic liberal supporters. As Sanders promises to stay in the race until the D.C. primary, there has been a split between his supporters as to whether he should stay in until the convention or bow out after the last primary.It s no secret: Clinton needs to pick a progressive populist to unite the party. Be it Sanders, Warren or Sherrod Brown, a more liberal counter to Clinton s progressive pragmatism will certainly reign in many of Sanders  most disenfranchised supporters.Even if Warren doesn t get the V.P. nod, there is no doubt she will be one of Clinton s strongest surrogates on the campaign trail. Her attacks on Trump are getting more polished, and clearly getting under his skin. When she called him out on his support for a housing market crash, his only response was to call her Pocahontas   a dead talking point from the right that didn t work in 2012, and certainly won t work in 2016.Couple her surrogacy with Obama, Biden and possibly Sanders by her side, Clinton would have a team that would be damn near unstoppable.Featured image via Chip Somodevilla/Getty Images