How top congressional aides are addressing increased fears they have for safety of lawmakers and their staff

Now in his 12th year as a U.S. House aide, Mitchell Rivard acknowledges he's increasingly worried about the harassment and threats against his colleagues — much more so than in the past.   

Rivard, the chief of staff to Democratic Rep. Dan Kildee of Michigan, said some of the calls made to his congressional office are at times so intimidating and so threatening that he tries to intervene to spare junior staffers from the hostility of the callers.

He said he now advises his staff to transfer these calls to his cellphone and to forward any threatening messages to him.