riga u.s. vice president joe biden tell baltic leaders tuesday take seriously comment republican presidential nominee donald trump call question u.s. commitment protect nato ally face russian aggression trip latvia biden suggest trump never hold elect office understand nato mutual defense guarantee know article five want make absolutely clear people baltic state pledge sacred honor unite state america ... nato treaty article five biden democrat say latvian capital fact occasionally hear something presidential candidate party ... nothing take seriously biden say biden visit come amid heighten tensions russia region nervousness among ally trump suggest might abandon nato pledge defend alliance members automatically elect democrats republicans support nato pledge say biden make remark appearance leaders three baltic state riga continue overwhelm bipartisan commitment unite state america political party maintain commitment nato say trump run democratic presidential nominee hillary clinton also affirm commitment nato clinton ahead poll lithuania latvia estonia three baltic state regain independence early 1990s half century annex soviet union see frontline potential conflict russia nato leaders agree last month deploy military force baltic state eastern poland first time increase air sea patrol reassure ally region worry threat moscow important us ready party confirm strategic partnership ... sure matter change elections unite state commitments ... nato baltic region stay say lithuanian president dalia grybauskaite speak biden russia often depict nato aggressor whose members move troop military hardware former soviet territory regard sphere influence wednesday biden travel turkey meet president tayyip erdogan prime minister binali yildirim visit sweden discuss europe asylum crisis biden tell baltic state n't take trump seriously