As Vice President Kamala Harris prepares to announce her running mate, a poll from The Associated Press-NORC Center for Public Affairs Research finds that several of the top contenders for the role are largely unknown to Americans. Arizona Sen. Mark Kelly stands out as one with more name recognition and higher favorability, particularly among Democrats.

The survey, which was conducted after President Joe Biden announced he was withdrawing from the race and Harris became the likely Democratic presidential nominee, highlights the strengths and weaknesses that different politicians could bring to the ticket — and the challenges they could face if selected.

Arizona Sen. Mark Kelly top voice as Kamala's running mate: Survey

Kelly, while better known and liked than some of the alternatives, is still unfamiliar to about half of Americans. And others, like Pennsylvania Gov. Josh Shapiro, while less known nationally, could draw on a deeper well of support in their home states and regions. Kelly and Shapiro are viewed among the front-runners, according to people familiar with the process, after the Harris campaign began its vetting with about a dozen names.

Harris said Tuesday she had not yet decided on her No. 2. But she, and whomever she selects, will head out on a seven-state swing of key battlegrounds, including Pennsylvania, Arizona and North Carolina, next week.