A California poll of Democrat primary voters in the state has Sen. Elizabeth Warren (D-MA) surging past favorite daughter Sen. Kamala Harris (D-CA) and former Vice President Joe Biden in the Golden State ahead of the second debates upcoming at the end of July.

The tracking survey of 4,050 respondents, conducted by Capitol Weekly, has Warren at 24.8 percent in California, while Harris is at 20.3 percent and Biden is at 19.6 percent. Sen. Bernie Sanders of Vermont is at 15.6 percent and South Bend, Indiana, mayor Pete Buttigieg is down at 7.7 percent. The only other candidate to break the 2 percent threshold, at 2.4 percent, is former Rep. Robert Francis “Beto” O’Rourke (D-TX).

2020 California Democratic Primary:

Warren 25%

Harris 20%

Biden 20%

Sanders 16%

Buttigieg 8%

O'Rourke 2%

Booker 1%

Klobuchar 1%@Capitol_Weeklyhttps://t.co/nnqQaAY6wA pic.twitter.com/5waQ0MVfKr — Political Polls (@Politics_Polls) July 16, 2019

The fact that Warren is leading Harris and Biden in California, one of the biggest states in the union and an important early battleground state should the race last longer than just Iowa, New Hampshire, and South Carolina, is particularly important and interesting. It suggests that Harris, who led a different survey out this week in California by one point over Warren, is having difficulty locking up her home state. It also suggests Biden is on the decline in a big way in key Democrat states, and will need to lock in some solid victories ahead of California in states like Iowa or South Carolina if he is to win the nomination. South Carolina polling has had Biden with consistent strong leads over the rest of the field.

The previous California survey, from Change Research, had Biden down in fourth place in California at 17 percent, with Harris out in front at 23 percent and Warren right behind her at 22 percent. Sanders came in third in that survey at 20 percent.

While Warren is out in front in the new Capitol Weekly poll, there are also some interesting data points when it comes to survey respondents’ second choice–with regard to both Harris and Warren.

“While the initial vote is the most watched metric, there are underlying measures that can also be extremely valuable to track over time. One of these is the ‘second choice’ of voters – those candidates who are consistently viewed as a backup option for voters as their primary choice might falter later in the process,” Capitol Weekly wrote in a piece about the survey data. “On this metric, we see Harris and Warren consistently at the top of the rankings.

Within the CA120 tracking infographic you can actually select any candidate to identify whose voters are likely to support as a second choice. Harris is the second choice of backers of every single candidate in the poll (including the recently exited Congressman Eric Swalwell) except for those who prefer Sanders, whose support goes to Warren as a second choice.”