It’s a fascinating split, in both political and economic terms.

Lt. Gov. Ralph Northam wants federal officials to exclude Virginia from offshore drilling, bucking the Democratic establishment of which he’s a member.

In doing so, Northam, who is running for governor in 2017, is going against fellow Democrats Gov. Terry McAuliffe and U.S. Sens. Mark Warner and Tim Kaine, not to mention a host of Republican politicians.

Yet it isn’t that hard to explain why Northam, a physician who describes himself as a conservative on fiscal issues and a liberal on social ones, is making his stand.

For one reason, he was born on the Eastern Shore, where many people make their living from the Chesapeake Bay and the Atlantic Ocean.

Proponents of offshore oil and gas drilling say it could add $2.2 billion to the state’s economy and create 25,000 jobs by 2035.

But that’s actually small beer compared with the hundreds of thousands of Virginians who make their living in water-related tourism and in the defense sector, especially the Navy. A smaller number earn money from fishing.

All three sectors are opposed to offshore drilling because it could put them at risk. Hotel owners don’t need spilled oil on beaches. The Navy needs open waters off the coast for ships to maneuver. And as shown by the 2010 Deepwater Horizon disaster, a major spill can put a huge dent in seafood catches.

Northam lives in Norfolk and is much closer to these local constituencies than his fellow Democrats, including President Barack Obama, who also backs offshore drilling.

Another problem is that while there may be natural gas offshore, there’s no hard data showing large oil reserves.

The big question seems to come down the simple mathematics, counting up jobs that already are supporting the state and assessing the risk.