Tammy Duckworth is running for Senate

Democratic Rep. Tammy Duckworth of Illinois announced Monday that she's challenging Sen. Mark Kirk, one of the most vulnerable Republicans up for re-election in 2016. She is the first Democrat to officially enter the Senate race.

In an online video, the two-term congresswoman shares her biography with Illinois voters, highlighting some of the economic hardships her family went through during her childhood. She financed her way through college with "loans, Pell grants and lots of waitressing," Duckworth says.

"If you don't give up on yourself, our nation should never give up on you, either," she adds.

The congresswoman notes that she is a combat veteran who lost both of her legs in Iraq in 2004, when her helicopter was shot down. The Senate's first female combat veteran -- Sen. Joni Ernst of Iowa -- was elected last year.

Duckworth also touts her sponsorship of the "No Budget, No Pay" Act, as well as how she "led by example" by returning $10,000 of her own salary to taxpayers in 2013.