JEFFERSON CITY, Mo. (AP) -- The water wars are raging again in America's heartland, where drought-stricken states are pleading for the increasingly scarce water of the Missouri River — to drink from their faucets, irrigate their crops and float the barges that carry billions of dollars of agricultural products to market.
From Montana to West Virginia, officials on both sides have written President Barack Obama urging him to intervene — or not — in a long-running dispute over whether water from the Missouri's upstream reservoirs should be released into the Mississippi River to ease low water levels that have imperiled commercial traffic.
The quarrel pits boaters, fishermen and tourism interests against communities downstream and companies that rely on the Mississippi to do business.
"We are back to the age-old old battle of recreation and irrigation verses navigation," said Sen. Claire McCaskill, a Democrat from Missouri.
If the water is held back, downstream states warn that shipping on the Mississippi could come to a near standstill sometime after Christmas along a 180-mile stretch between St. Louis and the southern Illinois town of Cairo. But if the water is released, upstream communities worry that the toll of the drought could be even worse next year for farms and towns that depend on the Missouri.
Obama has not decided whether to enter the dispute, nor has the White House set a timetable to respond. But tensions are rising in this decades-old battle.
From his perch as executive director of the Southeast Missouri Regional Port Authority, Dan Overbey watched this week as workers scrambled to ship out as much grain as possible before the Mississippi gets so low that it is not economically feasible or physically possible to move loaded-down barges.
"I don't know if we'll have, 'How the Grinch Stole the River' here," Overbey said. But if there is water to spare, "it would be a good thing to do."
More than 800 miles to the northwest, Michael Dwyer was also stewing. He's the executive vice president of the North Dakota Water Users Association.
To Dwyer, the downriver interests are "taking selfishness" to "a level you can't even comprehend."
"We suffered the impact of these reservoirs" when they were created decades ago by dams that flooded 500,000 acres of bottomland, Dwyer said. "To have some use of the resource only seems appropriate."
At the Mississippi River port near Cape Girardeau, Mo., about a million tons of cargo are loaded or unloaded annually, providing about 200 jobs, Overbey said.
The water is also vital in parts of the Dakotas, where the dammed-up Missouri River has spawned a tourism industry centered on boating and fishing.
Todd Martell serves as a guide for walleye fishing in the summer and also runs an upholstery business in Pierre, S.D., that makes custom boat covers and interior furnishings. Lower water levels don't necessarily hurt the fishing but can leave certain boat ramps high and dry, he said.
Over the past three decades, more than a dozen lawsuits have been filed challenging the management of the river, many of which set Missouri and other downstream states against the Dakotas and other upstream states.
The battles started in 1982, when Missouri, Iowa and Nebraska challenged a government contract allowing water to be drawn from the Missouri River in South Dakota to flush coal through a pipeline to power plants in the southeast. The U.S. Supreme Court blocked the project, but other lawsuits followed, including an effort by upstream states to reduce the water released from dams in an attempt to boost sport fishing in the reservoirs.
Missouri, meanwhile, sued the Army Corps of Engineers when it held back water because of droughts and shortened the navigation season. Environmental groups also joined the court battles, advocating for spring surges and summer declines in downstream river levels to help threatened species of birds and fish.
So far, no lawsuits have been filed in the current competition for water. But battle lines have been drawn.
In May, North Dakota Sen. John Hoeven teamed up with Sen. Roy Blunt of Missouri to tour dams and levees along the Missouri River a year after devastating floods in 2011. The Republicans stressed their desire to work together to improve flood control and river management. Now they are on opposing sides.
"There are times when they need to get rid of water, and we need to appreciate what we have to do about that," Blunt said. "And there are times when we need water, and they need to appreciate the fact that we need that water, even though they'd rather not get rid of it."
Said Hoeven: "Obviously, we're not going to be in agreement all the time."
Senators from 17 states along the Mississippi and Ohio rivers sent Obama a letter urging him to intervene and release water from Missouri River reservoirs. A day later, 15 officeholders from upstream Missouri River states countered with a letter warning the White House that intervention would be unlawful and would "only exacerbate the drought-related losses already experienced" by towns, Native American tribes and industries that rely on the Missouri River.
The Corps of Engineers, which manages both the Missouri and Mississippi rivers, says its guidelines prohibit it from releasing water from the Missouri River reservoirs for the primary purpose of improving navigation on the Mississippi. That position was backed up by a 1990 report from the federal government's General Accounting Office, though officials from downstream states believe Obama could trump that by declaring an emergency to avoid an "economic calamity."
Martell said it's hard to envision a truce in the water wars.
"The years we've really needed the water to stay here, it's gone," he said. "And then when we let it go, they complain about that, too. I don't think there's any happy medium, to be honest with you."