By Drew Griffin and Kathleen Johnston

HERLONG, California (CNN) - If you need an example of why it is hard to cut the budget in Washington look no further than this Army depot in the shadow of the Sierra Nevada range.

CNN was allowed rare access to what amounts to a parking lot for more than 2,000 M-1 Abrams tanks. Here, about an hour's drive north of Reno, Nevada, the tanks have been collecting dust in the hot California desert because of a tiff between the Army and Congress.

The U.S. has more than enough combat tanks in the field to meet the nation's defense needs - so there's no sense in making repairs to these now, the Army's chief of staff Gen. Raymond T. Odierno told Congress earlier this year.

If the Pentagon holds off repairing, refurbishing or making new tanks for three years until new technologies are developed, the Army says it can save taxpayers as much as $3 billion.



That may seem like a lot of money, but it's a tiny sacrifice for a Defense Department that will cut $500 billion from its budget over the next decade and may be forced to cut a further $500 billion if a deficit cutting deal is not reached by Congress.

Why is this a big deal? For one, the U.S. hasn't stopped producing tanks since before World War II, according to lawmakers.

Plus, from its point of view the Army would prefer to decide what it needs and doesn't need to keep America strong while making tough economic cuts elsewhere.

"When a relatively conservative institution like the U.S. military, which doesn't like to take risks because risks get people killed, says it has enough tanks, I think generally civilians should be inclined to believe them," said Travis Sharp a fellow at the defense think tank, New American Security.

But guess which group of civilians isn't inclined to agree with the generals on this point?

Congress.

To be exact, 173 House members - Democrats and Republicans - sent a letter April 20 to Defense Secretary Leon Panetta, urging him to continue supporting their decision to produce more tanks.

That's right. Lawmakers who frequently and loudly proclaim that presidents should listen to generals when it comes to battlefield decisions are refusing to take its own advice.

If the U.S. pauses tank production and refurbishment it will hurt the nation's industrial economy, lawmakers say.

"The combat vehicle industrial base is a unique asset that consists of hundreds of public and private facilities across the United States," the letter said. The outlook for selling Abrams tanks to other nations appears "stronger than prior years," the letter said. But those sales would be "inadequate to sustain the industrial base and in some cases uncertain. In light of this, modest and continued Abrams production for the Army is necessary to protect the industrial base."

Lima, Ohio, is a long way from this dusty tank parking lot. The tiny town in the northwestern part of the Buckeye State is where defense manufacturing heavyweight General Dynamics makes these 60-plus-ton behemoths.

The tanks create 16,000 jobs and involve 882 suppliers, says Kendell Pease, the company's vice-president of government relations and communications. That job figure includes ancillary positions like gas station workers who fill up employees' cars coming and going to the plant.

Many of the suppliers for tank manufacturing are scattered around the country so the issue of stopping production or refurbishment becomes a parochial one: congressional representatives don't want to kill any jobs in their districts, especially as the economy struggles during an election year.

"General Dynamics is not the industrial base," Pease said. "It is small vendors."

But General Dynamics certainly has a stake in the battle of the tanks and is making sure its investment is protected, according to research done by The Center for Public Integrity, a journalism watchdog group.

What its reporters found was General Dynamics campaign contributions given to lawmakers at key times, such as around congressional hearings, on whether or not to build more tanks.

"We aren't saying there's vote buying" said Aaron Metha, one of the report's authors. "We are saying it's true in pretty much all aspects of politics - but especially the defense industry. It's almost impossible to separate out the money that is going into elections and the special interests. And what we found was the direct spike in the giving around certain important dates that were tied to votes."

Pease said General Dynamics is bipartisan in its giving and there is nothing suspicious in the timing of its donations to members of the House and Senate. The giving is tied to when fundraisers are held in Washington - which is also when Congress is in session, he said.

Lawmakers that CNN interviewed denied that donations influenced their decisions to keep the tanks rolling.

Rep. Buck McKeon, a Republican from California and chairman of the House armed services committee, said he didn't know General Dynamics had given him $56,000 in campaign contributions since 2009 until CNN asked him about it.

"You know, the Army has a job to do and we have a job to do," McKeon said. "And they have tough choices because they've been having their budget cut."

McKeon said he's thinking about the long range view. "... If someone could guarantee us that we'll never need tanks in the future, that would be good. I don't see that guarantee."

Similarly, his Democratic counterpart on the committee, Rep. Silvestre Reyes, who has received $64,000 from General Dynamics since 2001, said he is worried about the workforce if the Lima plant is closed for three years.

"Listen, we don't want to play Russian Roulette with the national security of this country," Reyes said.

Odierno explained to the committee that it would be cheaper to shut down the tank plant and then restart it in 2017. But his plea was ignored.

"Lima would cost us $2.8 billion just to keep that open and our tank fleet is in good shape and we don't need to because of the great support that we have gotten over the last two years," he told the committee.

But General Dynamics said it will cost a lot less to keep the plant open. Pease said the Army hasn't factored in the huge costs of closing the plant and the potential loss of skilled workers who will be needed come 2017 when the Army plans to remodel the Abrams tank.

"It's not whether they need those tanks, it's how much it costs to restart it," said Pease. General Dynamics, he said, will survive with or without refurbishing tanks over the next three years.

So how did Congress respond to Gen. Odeirno's request to shut down production until 2017?

The answer came in the proposed congressional budget for next year. It includes $181 million for tanks the Army doesn't want or need now. That begs another question: who will likely get the money for the 70 or so tanks covered by that contract when it goes out for bid?

"General Dynamics would probably get the contract for it anyway because they are kind of the ones that are out there leading the way on this," said McKeon.

The Army tank battle sends an unsettling message to the Defense Department, says Sharp, with the defense think tank. But it's a message that may not surprise a public weary from decades of battles and horse-trading that have defined Capitol Hill.

"The fact that the military is having such a hard time getting this relatively small amount of money to be saved, I think is an indication of the huge uphill fight that the military faces when it comes to Congress," Sharp said. "Congress is going to fight tooth and nail to protect defense investments that benefit their constituents and the people that live in their states."

Maybe the next time the generals go up to the Hill, they should take a cue from the well-protected tanks parked in California. Perhaps they might consider wearing body armor.

CNN's Sara Anwar contributed to this report.