The race is currently considered a tossup by outside observers and polling has Ernst and Braley in a dead heat.
The election is expected to be a tossup in this heavily Cuban American South Florida district.
Obama, meanwhile, was also going door to door—doing a satellite tour of local stations in the tossup states.
It may not be news when John Boehner holds a fundraiser for the Republican candidate in a tossup district.
The nonpartisan Cook Political Report has currently classified the Colorado Senate race as a tossup.