Democratic frontrunner Hillary Clinton is on a lookout for a running mate who will be able to appeal to Bernie Sanders’ supporters and also efficiently combat presumptive Republican nominee Donald Trump. Eyes are on Massachusetts Senator Elizabeth Warren as she has already created a stir through her attacks on Trump on social media.

People close to Clinton’s campaign have been persuading her to select Warren as her running mate. However, chances of that happening are less as Warren has refused to confirm whether she would accept such as offer if made.

The Washington Post reported that Clinton and Warren are not in the best of terms, which could be one of the reasons to why such an alliance is unlikely. Warren will have her own agenda and goals which may not match with Clinton’s as the president.

Also, if Clinton chooses Warren as her vice-president, she will have to step down as the Massachusetts senator. In that case, Massachusetts’ Governor Charlie Baker, who is a Republican, will choose a temporary successor to that seat and which can pose a risk to Clinton’s presidency.

Warren has been gleefully carrying out a war on Trump on Twitter, which the real estate magnate seemed to be quite annoyed about. In a recent interview, Trump referred to her as “Pocahontas.” But Warren appeared to be in no mood to back down.

However, if Warren is not selected as Clinton’s running mate, the choice should be someone who would appeal to the younger demographic of the party which is being identified as the independent, as well as to the left of Hillary Clinton.

“We’re no longer playing the Bill Clinton-era win-the-middle, win-the-Reagan-Democrats presidential election politics,” USA Today quoted Jamal Simmons, a Democratic strategist who worked in Bill Clinton’s administration, as saying.

“People have gone to their corners, and you’re wearing a red jersey or a blue jersey. The question is, can you get enough blue jerseys to show up? That’s your first test.”