Story highlights Senate Democrats must defend 23 seats in next year's midterm elections

Republicans only need to defend eight seats

The Axe Files, featuring David Axelrod, is a podcast distributed by CNN and produced at the University of Chicago Institute of Politics. The author works for the podcast.

Washington (CNN) The progressive left should not apply ideological purity tests to Democratic senators who face tough re-election campaigns in 2018 in states President Donald Trump won handily last year, says Sen. Kamala Harris.

"We need those numbers," the California Democrat told David Axelrod on "The Axe Files," a podcast from the University of Chicago Institute of Politics and CNN.

Senate Democrats face a daunting challenge in next year's midterm elections when they must defend 23 seats (as well as the seats of two independents who caucus with the Democrats) compared with just eight seats the Republicans must defend, many of which are in states that Trump won in November.



challengers to Democratic lawmakers who cooperate with Trump in any way. Their task was potentially complicated when progressive activists and veterans of the Bernie Sanders presidential campaign formed a new political action committee called We Will Replace You , which has vowed to back primarychallengers to Democratic lawmakers who cooperate with Trump in any way.

Sen. Kamala Harris participates in a reenacted swearing-in with U.S. Vice President Joe Biden in the Old Senate Chamber at the U.S. Capitol on January 3, 2017 in Washington, DC.

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Harris vowed to campaign for her red-state colleagues -- even if they stray from Democratic orthodoxy on some issues -- and called for the party to unite in order to beat back Trump's policy priorities. Harris vowed to campaign for her red-state colleagues -- even if they stray from Democratic orthodoxy on some issues -- and called for the party to unite in order to beat back Trump's policy priorities.

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