National Democrats have privately fretted that there are too many candidates running for competitive seats in California's House primaries this summer, but they got one step closer to a smaller field Tuesday in one of the state's most closely-watched contests. 

Potential candidate Jay Chen said that he won't file to run in CA-39, the seat held by retiring Republican Ed Royce and one of Democrats' best pickup opportunities if they can avoid splitting the vote in the top-two primary in June.

"As of now 9 Democratic candidates and 7 Republican candidates have filed for a primary in which Republican turnout may remain higher than Democratic turnout," Chen said in a statement. "The probability of two Republicans advancing in November, and Democrats squandering a historic opportunity, is real."

"The greatest contribution I can make right now is to help consolidate the field, by stepping away from it. We cannot afford to let this seat slip away, and we must all put the greater good over personal ambition," he added. 

The DCCC praised the move in a statement. 

“The character that Jay Chen has demonstrated is exemplary, and clearly he has a bright future where he will continue to fight for his community, his constituents, and the progressive causes that matter to them," said DCCC chairman Ben Ray Lujan in a statement.