An Independent Senate candidate from Montgomery County named Rob Sobhani has caught the attention of several Maryland Democrats with a major television advertising blitz in a challenge to Sen. Benjamin Cardin (D).

According to the Maryland political blog “Maryland Juice,” Sen. Barbara Mikulski (D) sent out a concerned fundraising solicitation to Cardin supporters about the $700,000 ad buy.

Several of those Sobhani spots aired Sunday night on broadcast television.

Democratic sources on the ground say that $700,000 warrants attention, but they maintain that Cardin should still coast to re-election. Former Secret Service agent Daniel Bongino is the Republican nominee. Roll Call rates this race as Safe Democratic.