Staff file photo / U.S. Sen. Lamar Alexander touches a cannon as he looks into the Chattanooga valley during a visit to Lookout Mountain's Point Park in 2018. Alexander is pushing a bill he says will help address maintenance backlogs at national parks.

Tennessee statesman Lamar Alexander stands tall like a tree with his renewed push to pass what he's dubbed the Restore Our Parks Act before he retires from service in the U.S. Senate in 2020.

Alexander, 79, rarely misses an opportunity to remind us that he was born in the foothills of the Smoky Mountains and loves all things outdoors. Yet through his many years in state and federal government, Tennessee's signature national park in the Smokies has amassed a $162 million backlog in deferred maintenance.

That's a lot of money, but the staggering figure pales beside the nation's $12 billion backlog in deferred park needs.

America's parks need repair and upgrades to thousands of roads, bridges, bathrooms, lodges and emergency response systems. Those needs are part of the price that comes with our parks' popularity. The Great Smoky Mountains National Park alone in 2018 saw no fewer than 318 million visitors. That's a lot of wear and tear.

It's also a lot of dollars that are hard to come by, despite the fact that these parks are cash registers for the communities they serve.

Just in the Tennessee region, visitors in 2017 spent more than $154 million along the Natchez Trace Parkway, ending in Nashville.

(Read more: Restore Our Parks Act passes Senate committee, addresses repairs needed at Chickamauga and Chattanooga National Military Park)

Chickamauga and Chattanooga National Military Park hosted more than 1 million visitors in 2016, and those tourists spent more than $66.1 million here.

The Smokies drove $953 million in visitor spending to the East Tennessee and western North Carolina region.

And all of that tourism and recreation spending provides livelihoods to owners and workers in local restaurants and hotels, attractions, tour guide businesses, fly-fishing companies, sports outfitters and other firms that rely on park tourists each year.

Alexander introduced the Restore Our Parks Act in 2018 to cut the needs backlog in half by creating a dedicated revenue stream.

His plan would accomplish that by establishing a fund in the U.S. Treasury to be fed by up to $1.3 billion each year in unallocated energy royalties on U.S. public lands through 2023.

Some think that's a great idea.

But some worry that it might bring unintended consequences — such as a flood of interest from Congress, parks officials and even energy wildcatters looking to seek oil, gas and coal leases on our public lands. That concern springs in part from a July story in Bloomberg News that oil and gas industry groups are becoming more vocal in supporting this bipartisan legislation. Oil and gas groups say the legislation would show the value of producing fossil fuels on public land, even as several Democratic presidential candidates support blocking such leasing on federal lands to address climate change, according to Bloomberg.

Western Energy Alliance, which represents oil and gas producers on federal lands in the West, is publicly supporting it because they say its measures promote oil and gas development and create "a reasonable regulatory environment." And already, the American Petroleum Institute — and the Trump administration's energy agenda — calls for expanded access to oil and gas leasing on federal lands in order to maintain national parks.

But no one — least of all Alexander — would want to see an energy extraction operation in the Smokies cove where rare synchronous fireflies put on a show each spring, or anywhere else like that.

Anders Reynolds, the federal legislative director of the Southern Environmental Law Center, a mammoth, nonprofit group of attorneys who use the power of the law to champion the environment of the Southeast — says there is no language in the bill that opens up new land to energy leases or new development. Rather, the bill just talks about existing royalties and using them to improve the parks.

"That's a good solution to a big problem, and it has bipartisan support, it's popular and we support it," Reynolds said, adding that the bill is co-sponsored by 330 members of the House and 45 senators.

The National Parks Conservation Association also supports the legislation.

The key now is whether Alexander can muscle it through. The measure already has passed out of both House and Senate committees.

The further key, of course, is whether Alexander's successors — and peers in the Senate and the House — can stand tall against any future park assaults.