For Democrats hoping to take back control of the House this year, California is key.
Grassroots groups have sprung up around the state in recent months. Many of them are backing candidates hoping to challenge incumbent Republicans. But you can't run a campaign on pure enthusiasm; it takes money.
Well, according to campaign filings, that's just what Democrats have.
At least half of 14 incumbent Republicans were outraised by opponents in 2017. But is money an indicator of future success?
Professor Jack Pitney says it definitely doesn't hurt.
It doesn't necessarily guarantee success, but failure to raise money guarantees defeat.
When you're able to collectively raise more money than the incumbent, that's clearly a sign of incumbent weakness and strength from the challenging party.
Pitney is the Roy P Crocker Professor of Politics at Claremont McKenna College.