California Gov. Gavin Newsom is pushing the state Legislature to tackle what has long been one of the biggest gripes about government: Taking far too long to build things like roads and bridges.

But Newsom’s plan to cut through red tape has slowed in the state Legislature, where some lawmakers fear his true motive is to favor a single project — the long-delayed and long-disputed plan to build a giant tunnel to re-route how the state moves water from north to south. The tunnel reflects the tension between arid Southern California, where most of the people live, and Northern California, the source of most of the state’s water.