Notwithstanding his penchant for obscure philosophical aphorisms, sometimes delivered in Latin, at his core Jerry Brown is a largely conventional politician.

Therefore, while he repeatedly denies it, as political protocol dictates, he certainly is concerned with the legacy he’ll leave when his record-long, bifurcated governorship ends 18 months hence.

Of course, there will be the paper record of budgets and bills, of executive orders, and of elections won and lost. But politicians instinctively want to leave behind more than yellowing files in dusty boxes – or their electronic equivalents. They want concrete reminders of what they wrought while in office.

For Brown, that means two massive public works projects – twin tunnels beneath the Sacramento-San Joaquin Delta to carry Sacramento River water southward, and a north-south bullet train.

Both are highly controversial, sparking regional and ideological conflict, both face daunting regulatory hurdles and, perhaps most importantly, there are no clear pathways for covering their combined costs approaching $100 billion.

The water tunnels would more or less complete the state water system that was the most visible accomplishment of Brown’s father and gubernatorial predecessor, Pat Brown.

The tunnels got a boost last week when two federal wildlife agencies concluded that they wouldn’t worsen the Delta’s already damage habitat.

However that’s just one of the many regulatory hurdles for WaterFix, as it’s officially dubbed, the most important being an incredibly complex evaluation by the state Water Resources Control Board of its impacts.

Even if the $17 billion project clears all those hurdles, it still faces litigation from environmental groups and other opponents and must receive commitments from San Joaquin Valley agricultural water districts and Southern California’s Metropolitan Water District for construction funds.

The once-vigorous support from both factions has cooled markedly because of project costs and the likelihood that they would be paying for more reliability of deliveries, but little or no new water.

The Metropolitan Water District’s largest member, the San Diego County Water Authority, is openly critical, doubting whether the tunnels are worth raising bills of residential and commercial water customers, and the Met, as it’s called, has yet to make a final commitment. Nor have the San Joaquin Valley farm water groups.

The bullet train would cost at least four times as much as WaterFix and while the state has enough state bond and federal grant money to continue a starter line in the San Joaquin Valley, authorities have yet to pin down funds to extend it north or south.

So far, the hoped-for investment from private sources or other governments, such as China, has not materialized, largely thanks to skepticism about ridership projections and a law that bars operating subsidies from the state.

The project gets a big chunk of proceeds from auctions of greenhouse gas emission allowances under the state’s cap-and-trade program, but auction results have been spotty and will dry up altogether if the program is not extended beyond 2020.

Brown is seeking reauthorization of cap-and-trade, and officials have talked about using its revenues to service a massive construction bond for the bullet train’s next phase. But so far, the governor has not been able to make a legislative deal.

Both projects, then, are iffy. Brown may depart before their fates are known and even if they are built, there are no guarantees that they will be viewed positively by future generations or as Brown’s twin follies.