new york/washington u.s. senator elizabeth warren consider idea serve hillary clinton run mate see obstacles choice prepare endorse presumptive democratic presidential nominee several people familiar warren think tell reuters think could evolve warren concern join clinton ticket include question whether run two women would give democrats best shoot defeat republican donald trump one source say advisers warren fiery critic wall street popular figure among progressive democrats close contact clinton campaign team conversations increase frequency recent weeks source say warren signal people close intrigue possibility clinton discuss role clinton 68 anyone else campaign people say warren 66 one democrats outspoken critics trump 69 priority help defeat presumptive republican nominee nov. presidential election source say warren also commit advance political agenda describe progressive clinton centrist position warren fear vice president cabinet position voice could less hear u.s. senate priority issue address income inequality source say past warren accuse clinton abandon support strong bankruptcy legislation try appease wall street endorsement clinton could come within week two one source say clinton appeal democratic party unity twitter weekend warren echo call emphasize importance party come together beat trump get ready donald warren tweet come warren represent massachusetts u.s. senate stay neutral democratic primary race notably remain woman senator throw support behind first woman presidential nominee major u.s. political party join clinton ticket could help energize progressives win supporters clinton rival bernie sanders democratic socialist u.s. senator vermont sanders call rein wall street break big bank dovetail warren view ongoing feud trump gain steam social media series post label celebrity businessman racist sexist xenophobic say go fight make sure toxic stew hatred insecurity never reach white house warren join clinton late last month criticize trump root 2008 financial crisis deliver 10-minute invective subject annual washington gala two weeks ago kind man root people get throw house tell exactly kind man warren say man care one small insecure money-grubber care get hurt long make profit it trump ridicule warren call pocahontas mock reference say past native american ancestry pocahontas famous native american early colonial virginia warren due speak american constitution society progressive legal group thursday time democrats republicans criticize trump comment mexican-american judge gonzalo curiel exclusive clinton ally warren weigh potential vp role see hurdle source