WASHINGTON — The California Valleycrat could be an endangered species.

Or maybe it was mostly mythical all along.

A storied political hybrid, the Valleycrat stresses regional loyalty first and foremost. Party labels seem secondary. Bipartisan cooperation is commonplace, particularly on farm and water issues. Cross-party personal relationships are warm or at least respectful.

Now? Not so much.

“That’s gone from both parties, there’s no question about it,” said former San Joaquin Valley congressman John Krebs, a Democrat. “Now, the well is so poisoned.”

In the past decade, relations have frayed and partisanship has increased. It often seems that Rep. Devin Nunes, R-Visalia, and Rep. Jim Costa, D-Fresno, can barely hide their mutual loathing. Breaking a live-and-let-live tradition, Valley lawmakers are explicitly trying this year to unseat their colleagues.

In Sacramento, some Valley legislators face attack from members of their own party if they don’t toe the partisan line. In Washington, House Republicans have been writing a California water bill for the past year without letting Democrats into the room.

“For three decades or longer, Valley Democrats and Republicans worked together. We had far more in common than what differences we had,” Costa said. “All that has changed in the last couple of years.”

Not everyone agrees.

Freshman Rep. Jeff Denham, who recently moved his residence from Atwater to Turlock, insisted relations among Valley lawmakers are "good and getting better," noting that he is meeting with Costa the week of Feb. 6. Nunes, while saying the notion of a moderate Valleycrat "is gone," added that "where we can work together, we work together."

Still, Republican political analyst Tony Quinn and Fresno Republican and former Secretary of State Bill Jones agreed there has been a demise of the Valleycrat in part to the congressional and legislative districts that were drawn after the 1980 census.

The partisan gerrymandering ushered in a decade of Democratic Party dominance in California. In the process, it politically segregated parts of the Valley along racial lines, Quinn said.

A one-time Fresno County supervisor, Krebs served in the House of Representatives between 1975 and 1979. It seemed a golden era for Valleycrats.

Texas native-turned-San Joaquin Valley resident Bernie Sisk, a fellow House Democrat, was tending to the region’s farmers with the help of conservative Southern allies. From Roseville, in the Sacramento Valley, business-friendly Democrat Harold “Bizz” Johnson was pushing roads and dams with GOP help.

In 1970, the late Republican Ken Maddy won 57 percent of the vote in an Assembly seat that had just 31 percent registered as Republicans. He went on to represent the region for nearly three decades before term limits forced him out of office in 1998.

When Maddy died of cancer in 2000, then-Assembly Speaker Antonio Villaraigosa of Los Angeles called him “the prototype of the legislator who works across the aisle to get things done.”

By that time, however, another controversial reapportionment was coming. Jones called the 2001 redistricting plan an “unholy alliance between Republicans and Democrats” that gave incumbents of both parties highly partisan districts — and safe seats.