Editor’s note: The presidential nominating contests in both parties will come down to the California primary.

For Democrats, 548 delegates are at stake — 11.5% of the total. For Republicans, 172 delegates are at stage — 6.9% of the total. Of those, for Democrats, 158 (29%) are divided proportionally on a statewide basis, while 317 (58%) are divided proportionally by congressional district, with each district providing between 5 and 8 delegates. The remaining 73 (13%) are “superdelegates.”

For Republicans, 13 (8%) are awarded statewide, with ten going to the candidate with the highest number of votes on a winner-take-all basis, and three going to “pre-determined” delegates (the State Chair, National Committeewoman, National Committeeman). Meanwhile, 159 (92%) are awarded by congressional district on a winner-take-all basis, with each district providing 3 delegates.

The result: a district-by-district battle in both parties, which we preview for you here.

CA-25: This district is home to the Ronald Reagan Presidential Library, and much of the northern portion of Los Angeles County, which includes many of the county’s most conservative areas. In 2014, the congressional race saw two Republicans face off against each other in a messy, contentious battle; conservative Steve Knight won, and his opponent Todd Strickland is today one of Donald Trump’s most important organizers in the Golden State.

Prospects:

Democrats: The conservative profile of the district favors Clinton, though Sanders will also have some support.

Clinton 3, Sanders 2

Republicans: Cruz is leading in some polls of Los Angeles County Republicans because of districts like the 25th.

Cruz 3, Trump 0, Kasich 0

Joel B. Pollak is Senior Editor-at-Large at Breitbart News. His new e-book, Leadership Secrets of the Kings and Prophets: What the Bible’s Struggles Teach Us About Today, is on sale through Amazon Kindle Direct. Follow him on Twitter at @joelpollak.