Supporters arrive for a Democratic Party campaign rally in Morrow, Georgia, where former US president Barack Obama will join Senator Jon Ossoff as a special guest. (EPA Images pic)WASHINGTON: Nearly nine in 10 Americans believe government corruption is widespread - a consensus Democrats hope to capitalise on as voters make up their minds on whether to keep billionaire Donald Trump's Republicans in power.

Former president Barack Obama has hammered the message home in recent days as he stumps for Democratic candidates in must-win states, hoping to flip control of Congress.

Trump "is very much focused on enriching himself and his family and his cronies," Obama told a rally Wednesday in Georgia. "The guy has made billions of dollars while in office."