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Conservatives are rallying in support of a balanced-budget amendment in the run-up to a Friday vote, warning fellow lawmakers that it's just about the only way to ensure Congress follows through on vows to cut spending.

The debate comes the same week the national debt crossed the $15 trillion mark. The milestone was a timely reminder of Washington's hard-to-break habit of spending way more than it takes in.

As a bipartisan committee remains stuck on how to cut $1.2 trillion from the 10-year deficit, lawmakers skeptical about the government's fiscal track record pushed Thursday for the amendment.

"We need a fiscal fix that will last for generations," Rep. Lamar Smith, R-Texas, said. "If we want to make lasting cuts to federal spending, a constitutional amendment is the only solution. It is our last line of defense against Congress's unending desire to overspend and overtax."

Republicans earlier this year took up the rallying cry of "cut, cap and balance," the nickname for their budget plan to cut spending, cap future spending levels and back a balanced-budget amendment.

Little progress has been made on those fronts. Congress voted over the summer to cut spending by $900 billion, in exchange for a much bigger debt-ceiling increase. The so-called Super Committee was then tasked with finding another $1.2 trillion to $1.5 trillion in savings, if not more. But with a Wednesday deadline approaching, the GOP and Democratic members are at odds over how to balance tax hikes and spending cuts in pursuit of that target.

Some are talking about changing the rules of the Super Committee altogether.

With the committee clash as a backdrop, supporters of a balanced-budget amendment say it's critical.

The amendment, requiring that spending not exceed revenues in any given fiscal year, is essentially the same as one proposed the last time Republicans regained control of the House, in 1995. At that time it passed, with 72 Democrats joining 228 Republicans in voting yes. The measure fell just one vote short of getting the needed two-thirds majority in the Senate.

This time there are 242 Republicans, 12 more than in 1995, and only 48 Democrats are needed to come up with a two-thirds margin, but the outcome of the vote on Friday is far from certain.

The Democratic leadership is actively urging its members to vote against the amendment, and the White House has come out strongly against it. Democratic Whip Steny Hoyer of Maryland, who voted for the measure in 1995, is leading the effort to defeat it this time.

Hoyer said that in 1995 he didn't "contemplate the irresponsibility that I have seen fiscally" during the George W. Bush administration and in more recent months when "Republicans took America to the brink of default" over raising the debt ceiling.

Rep. Chris Van Hollen, D-Md., wrote in a letter to fellow lawmakers that the GOP proposal would deprive Congress of the "flexibility" to address national emergencies. He described the plan as a ploy to "impose the Republican budget priorities of deep spending cuts."

Rep. Robert Goodlatte, R-Va., the chief sponsor of the measure, said Americans "understand what it means to live within their means and they expect nothing less from the federal government. A balanced-budget amendment to the Constitution is the only way to ensure that Congress curtails its spending on an annual basis."

To attract Democrats, Republicans opted for the Goodlatte version, which does not, as many conservatives wanted, set a tight cap on government spending or require a supermajority to raise taxes. It does require a three-fifths vote by both chambers to raise the debt ceiling and a three-fifths vote to approve a deficit in any one year. Congress can also waive the amendment in times of serious military conflict.

The amendment has the overall support of the so-called Blue Dogs, a 25-member group of fiscally conservative Democrats.

"I think this is long overdue," Rep. Jason Altmire, D-Pa., told Fox News.

But other Democrats pointed to dire predictions of what could happen if a balanced-budget amendment were in effect. Some 275 labor and other mostly liberal groups wrote a letter to lawmakers saying that forced spending cuts or raised taxes needed to balance the budget when the economy is slow "would risk tipping a faltering economy into recession or worsening an ongoing downturn, costing large number of jobs."

Democrats also cited a report by the liberal Center on Budget and Policy Priorities estimating that, if there is not an increase in revenues, the amendment could force Congress to cut all programs by an average of 17.3 percent by 2018. It said that would mean hundreds of billions in cuts in Social Security, Medicare, Medicaid and the Children's Health Insurance Program.

The amendment would not go into effect until 2017, or two years after it is ratified, whichever comes later, and supporters say that would give Congress time to avoid dramatic spending cuts.

A constitutional amendment must be ratified by three-fourths of state legislatures.

Another issue of contention is how the amendment would be enforced. Neil Kinkopf, a law professor at the University of Georgia School of Law, said in a report he wrote for the American Constitution Society for Law and Policy that there could be "catastrophic consequences" if Congress fails to resolve disputes over how to reach balance.

"This would mean judges would be required to order either spending cuts or tax increases. This prospect is so troubling that it has justly alarmed commentators across the political spectrum."

But Sen. John Cornyn, R-Texas, argued that Washington can't be trusted to balance its books without new limits.

"Washington has shown that it cannot curb its unlimited appetite to spend money we simply do not have, opting instead to borrow billions from foreign countries that may not have our best interests at heart and to pass the buck to our children and grandchildren," he wrote Thursday in the Dallas Morning News.

The Associated Press contributed to this report.