washington democratic presidential hopeful hillary clinton struggle secure endorsement labor unions announce opposition keystone xl oil pipeline project support environmentalists oppose accord leak email publish wikileaks friday announce september 2015 oppose transcanada corp proposal build pipeline canada unite state campaign seek soften blow labor unions offer energy infrastructure plan would create job accord email internal campaign email august 2015 reveal difficulty clinton appease unions environmentalists fight party nomination ahead nov. election wikileaks publish clinton email hours u.s. government accuse russia campaign cyber attack democratic party organizations email clinton advisers discuss frame candidate energy infrastructure plan would call replace old pipelines repair rail track improve electric grid way would appeal labor unions yet endorse stage could mention ... transition hrc want create career within new energy economy career buzz word write nikki budzinski labor outreach director hillary america clinton long avoid take firm position keystone pending seven years seek party nomination last year secretary state clinton say 2010 incline approve rival senator bernie sanders staunch opponent pipeline president barack obama reject pipeline november 2015. labor unions push approval pipeline say would create thousands construction job environmentalists oppose would increase greenhouse gas emissions canada oil sand email show north america build trade represent builders construction workers contact campaign hear obama would announce denial pipeline late august clinton would say encourage make decision close get bldg sic trade endorsement right ok even though like write amanda renteria campaign national political adviser build trade union endorse clinton november laborers international union north america endorse clinton december clinton struggle please green labor group likely emerge key challenge win presidency decision another pipeline dakota access spark major protest native american environmental group obama administration temporarily halt construction frustrate unions type decisions make administration get dump presidential race kind unfair sean mcgarvey president north america build trade unions tell reuters interview last month like clinton energy policies think reasonable clinton campaign struggle balance unions environmentalists emails/wikileaks