Eliminating the tax, as Blunt, Graves and others have suggested, could add $250 billion or more to the federal deficit over the next 10 years, according to some estimates. Losing that revenue could complicate the math of any fiscal cliff compromise.

Even reducing the estate tax might provide a windfall for wealthy non-farmers. Three-fourths of the estate tax is now paid by heirs to the top 5 percent of earners, making it a tax that hits the children of the well-to-do while leaving out most low- and middle-income Americans.

More than 99 percent of estates owe no tax at all. Of estates that do pay the tax, only 6 percent are farms, the Congressional Budget Office said in 2005.

"The estate tax is best characterized as a tax on very large inheritances by a small group of wealthy heirs," said a recent statement from Chye-Ching Huang and Nathaniel Frentz of the Center on Budget and Policy Priorities.

Extending the current estate tax rates, as some have proposed, would cost the government $119 billion over 10 years, they said.

The Obama administration has proposed a middle ground. Its latest budget called for a 45 percent tax rate on estate values above $3.5 million, a plan that would hit roughly 7,000 estates, according to some estimates. It isn't clear if that plan will end up in whatever fiscal cliff agreement is reached.

The federal government began collecting an estate tax in 1916. President Theodore Roosevelt and others said heirs to great fortunes should not get a tax-free windfall when their parents died.

The Center on Budget and Policy Priorities makes a similar argument.

"It is appropriate that people who have prospered the most in this society help to preserve it for future generations through tax revenues that derive from their estates," it argues.

But Cope and other farmers insist they should not be considered rich, even though the value of their land has gone up. They are asset-rich, they say, but cash-poor.

"My farm is supporting three generations," he said. His rural Missouri ranch has been in the family since 1910.

He is 33 years old, with two children under 7 years of age.

"I want nothing more than for my children and my brother's children to have the same opportunities we've had," he said.