Senate Dems' campaign arm outraises GOP

Senate Democrats' campaign arm has again outraised its Republican rival.

The Democratic Senatorial Campaign Committee said Friday that it raised $7.2 million in June. The National Republican Senatorial Committee, meanwhile, raised $6 million.

The Democrats have outraised Republicans in 16 of the last 18 months this election cycle. Combined, the two major committees have raised almost $167 million.

Democrats are defending a slim majority in the Senate and Republicans have been aggressive in their criticism of endangered incumbents in North Carolina, Louisiana and Colorado.

Senate Democrats have $30.5 million in the bank to Republicans' $24.6 million