Newsom wanted to fast-track the Delta tunnel project. The Legislature slowed the flow

Repeatedly Gavin Newsom has sought legislative approval of his high-priority policy proposals within the annual state budget process, even though they often have nothing to do with the budget.

The unique rules governing the budget and its accompanying “trailer bills” allow them to be enacted quickly, bypassing many parliamentary hurdles and vote thresholds that other legislation must endure.

The Legislature, controlled by Newsom’s fellow Democrats, generally allows him to use the budget process, in part because legislators often employ the same shortcuts for their own priorities.

Their underlying motive for the sneaky use — or misuse — of the budget process is to avoid prolonged analysis and debate that might, if the bills’ contents are fully vetted, make them more difficult to enact. The trailer bills often contain favors for interest groups that would be difficult to justify in a more transparent process.

Last month, while unveiling a revised state budget, Newsom asked the Legislature to attach legislation that would fast-track the highly controversial project to move Sacramento River water to the California Aqueduct without it flowing through the Sacramento-San Joaquin Delta — renewing a tactic that failed two years go.

First proposed as a “peripheral canal” more than a half-century ago, it morphed into twin tunnels and, after Newsom’s election, a single tunnel. Its purpose has also evolved, from a mechanism to increase water deliveries to Southern California, to one that would, Newsom and others argue, improve the reliability of deliveries.

“For too long, attempts to modernize our critical water infrastructure have stalled in endless red tape, burdened with unnecessary delay,” Newsom said. “We’re done with barriers. Our state needs to complete this project as soon as possible, so that we can better store and manage water to prepare for a hotter, drier future. Let’s get this built.”

It would take a book —a big book — to fully explain all of the project’s environmental, financial and political aspects. Briefly, however, while advocates say that isolating water conveyance from the Delta would improve habitat for fish and other wildlife, opponents contend that less water flowing through the estuary would further degrade its water quality.

While Newsom and other supporters often depict the tunnel as a stand-alone project, it is inexorably related to other aspects of California’s very complex water picture.

For instance, as it touts a tunnel that would doubtless reduce Delta flows, the state also is pressuring farmers to reduce diversions from the San Joaquin River and its tributaries, to increase flows through the Delta. Those two efforts are not officially linked, but the connection is obvious.

The long-stalled Delta Conveyance Project — the latest of several official names — has slowly approached the final pre-construction phase, which is why Newsom wanted a trailer bill to finally get a green light.

However, his proposal immediately rekindled the political jousting between advocates and opponents and the pressure on legislative leaders over whether the tunnel should be addressed in a trailer bill.

This week the Legislature punted, its members clearly leery about taking on such a high-profile and infinitely controversial issue through the budget process, especially since Democratic legislators are very divided, roughly along north-south geographic lines.

With the budget process now off limits, the warring factions may duke it out through the normal legislative process, although there is a theory in some circles that the Department of Water Resources could proceed because the State Water Project was approved by voters 65 years ago.

The Legislature specifically approved the project as a canal more than 40 years ago, but its opponents challenged it in a 1982 referendum and won.

This could be, as the inimitable Yogi Berra once observed, “déjà vu all over again.”