Rep. Ann Kirkpatrick talks with Pusch Ridge Christian Academy art teacher Elmer Yazzie at a small ceremony for the winners of the local 2014 Congressional Art Competition, Thursday, August 14, 2014, in Oro Valley, Ariz.

Ann Kirkpatrick announced Tuesday morning she will challenge John McCain for a Senate seat in 2016.

She kicked off her campaign with an email to supporters, a new website and a YouTube video, all using her boots as a branding icon. Kirkpatrick's boots played a major role in her campaign for the U.S. House of Representatives last year.

Kirkpatrick is serving her third term in Congress. She won in 2014 with about 53 percent of the votes in Arizona's Congressional District 1, which includes Marana and Oro Valley. 

Kirkpatrick was first elected to Congress in 2008, but lost to Republican Paul Gosar in 2010. She was elected again in District 1 in 2012 after redistricting. She has worked closely with Gosar on a number of legislative priorities for the state.

"I know this isn't going to be an easy race. But I've got my boots on, my sleeves are rolled up, and I'm ready to work," Kirkpatrick said in the campaign email.

"Senator McCain welcomes Congresswoman Kirkpatrick to the race, and looks forward to running a vigorous campaign no matter who the Democratic nominee is," McCain spokesman Brian Rogers said in a statement.

Contact reporter Becky Pallack at bpallack@tucson.com or 573-4346. On Twitter: @BeckyPallack