There’s a big reason that Rep. Katie Porter’s first U.S. Senate campaign stop will be in the East Bay next week: Geography — perhaps as much as anything — will matter in the 2024 Senate race that began in earnest with Porter’s announcement Tuesday that she’s in.

If the race is between two Southern California candidates with largely similar progressive records — like Porter of Orange County and Rep. Adam Schiff, D-Burbank — the voter-rich Bay Area will go a long way toward deciding the winner. And that math will change now that sources have confirmed to The Chronicle that Rep. Barbara Lee, D-Oakland, is making plans to run. If Rep. Ro Khanna, D-Santa Clara, jumps in as well, the equation will grow even more complicated.