las vegas outside political money pour race nevada replace u.s. democratic senator harry reid retire tell reuters main reason favor successor win easily cash beyond state border race underscore rise outside money u.s. campaign finance well key demographic challenge face republican party catherine cortez masto joe heck dead heat replace senate democrat democrat cortez masto 52 two-term nevada attorney general win first latina elect u.s senate republican heck 54 three-term house representatives member physician u.s. army reserve general poll show tight race two tie 37 percent likely voters mid-august suffolk university survey seat contest one senate year republicans truly good chance flip control democrats would shield republicans senate majority threat elsewhere say interview heck campaign fuel outside money reid former boxer lash koch brothers u.s. chamber commerce karl rove chamber commerce nothing front anymore koch brothers karl rove raise money go koch brothers front koch brothers say reid 76 catherine go win koch brothers involve win 15 point reid say charles david koch wealthy industrialists spend millions dollars support libertarian-leaning candidates mostly republicans network group operate law let keep donors identities secret reid walk cane often appear dark sunglasses long war kochs certainly see fair share criticism senator reid want talk issue move toward politics personal attack say jam davis spokesman koch-aligned freedom partner action fund supreme court 2010 citizens unite decision open door tidal wave political spend corporations labor unions political cause candidates reshape u.s. campaign finance 20 political group include two koch-aligned organizations reid-aligned senate majority pac pour well 20 million nevada senate race far accord center responsive politics track campaign spend overall spend favor heck cortez masto nearly 2-to-1 freedom partner another koch-aligned group concern veterans america spend nearly million mostly ads portray cortez masto captive special interest rove formerly adviser republican president george w. bush republican activist co-founded republican super pac american crossroads spokesman ian prior call reid accusations rove kochs funny prior say look harry reid look bogeyman star dark fantasy movie cast himself u.s. chamber commerce large lobby group corporations washington closely align republican party reid allegations front kochs chamber spokesman blair latoff holmes say true certainly first time senator reid make unsubstantiated allegations nevada big city las vegas nearly three-quarters state population live near casino capital nevada reflect unite state grow racial diversity 1970 nevadans 87 percent white percent latino 2010 ratio 54 percent white 26 percent latino heck white manage get elect congress ethnically diverse congressional district split evenly republicans democrats democrats 72,000-vote registration advantage republicans nevada latinos help elect president barack obama 2008 2012. republican presidential nominee donald trump anger many latinos vow build wall mexican border deport undocumented alien heck endorse trump trump popularity crumble state stay within percentage point democratic presidential nominee hillary clinton nevada cortez masto keen link heck trump say interview heck follow trump example mud-slinging dirty campaign heck spokesman brian baluta say cortez masto distort heck record talk joe talk always vile negative way baluta say u.s. senate 's reid last round jab outside money nevada succession fight