Charles B. Rangel needs fuel for the first monster tax bill of his Ways and Means chairmanship, a proposed grab-bag that would simplify the tax code, eliminate the alternative minimum tax (AMT) and reduce taxes on middle-income families.

He must find nearly $1 trillion over 10 years, which creates an extraordinary political and fiscal challenge, especially because his efforts have received a lukewarm response in the Senate. Some of the money will come from higher rates on top earners, but Rangel, D-N.Y., coyly refuses to detail his revenue-raising plans.

As an experienced tax writer, Rangel is reluctant to specify his offsets, lest they be swiped for other projects or subject to early political attacks.

For now, he says he is seeking ideas that would simplify the tax code and meet a two-part test: Does it raise money? Can it get votes?

Unfortunately for Rangel, money and votes share an inverse relationship in this instance. The more he raises by targeting special tax breaks, the more lawmakers’ votes he stands to lose. And that’s the fundamental balancing act for the chairman as he prepares to introduce a bill this fall.

“We damn sure are going to have to try to close loopholes, simplify, see what money is out there, see what we would like to do, then see what we can afford to do, then see whether we can get this damn thing off the ground, in terms of getting support,” he said.

Risk-free offsets don’t exist, at least not those big enough to balance a revenue-neutral repeal of the AMT, which would cost $872 billion over 11 years. The rest of the package — enhancements to the child tax credit, the earned income tax credit and the standard deduction — would add $75 billion to $100 billion over 10 years.

The easiest approach would be to roll back some of President Bush’s tax cuts (PL 107-16, PL 108-27). Indeed, Rangel has said repeatedly that he wants to “adjust” top income tax rates, which those laws reduced. But such a rollback seems difficult before Bush leaves office.

Also, under congressional budget rules Rangel cannot claim any offset for rolling back Bush’s tax cuts beyond 2010, because that’s when those tax cuts are due to expire.

Though widely reviled, the AMT is no easy case. Because lawmakers have “patched” it by preventing the tax from reaching further into the middle class, many beneficiaries of its demise would not necessarily know it, diminishing the outcry for change. Moreover, the AMT disproportionately affects Democratic-leaning states such as Massachusetts and California, making it a tougher sell to other lawmakers.

Ways and Means Democrats have been talking for months about an AMT bill that is fully offset by rate increases. Rangel said he wants to look beyond rates and remove tax credits that he thinks are not working. Then, he says, he can specify the new rates. A House Democratic tax aide said any additional revenue would probably cover other items added to the bill, such as an extension of expiring tax provisions.

Rangel has ruled out big but wildly unpopular ideas for raising revenue, such as eliminating deductions for home mortgage interest and charitable contributions.

Democrats have offered some clues about what might end up in the bill. A recent hearing highlighted private equity managers, and Rangel’s package could include a measure (HR 2834) that would tax more of their pay as ordinary income, not capital gains. There is no official revenue estimate.

Democrats could codify the “economic substance” doctrine, a judicial precedent disallowing tax shelters that do not result in economic benefits to companies. Rep. Lloyd Doggett, D-Texas, has said his bill (HR 2136) would generate $13.6 billion.

Rangel also signaled that he may offer proposals to close the estimated $345 billion annual “tax gap” between taxes owed and paid. That could include a proposal to prevent underreporting of capital gains.

Rangel may encounter trouble in the Senate. Finance Chairman Max Baucus, D-Mont., expects Congress to pass another AMT patch this year, preventing it from expanding to more than 22 million taxpayers from 4 million currently.

“I’m assuming [the patch] will happen, though I assumed it would be patched some time ago,” Treasury Secretary Henry M. Paulson Jr. said in a recent meeting with reporters. “And the fact it’s going this late in the year and not being patched is a concern to me. And it’s a surprise to me, frankly.”

The pressure for a patch raises a tough question for House members: Will they cast a politically tough vote for Rangel’s ambitious tax overhaul if it is headed for near-certain death in the Senate? That’s no problem, replies Rep. Richard E. Neal, D-Mass., an architect of the tax plan.

About 90 million people would benefit, he noted, and a much smaller number would pay more. There is little political downside to voting with the masses, he suggested.

A strong House vote could put pressure on the Senate and Bush in the short run. It also could become the foundation for a post-election tax initiative, said Marc Gerson, an attorney at Miller & Chevalier and a former House Republican tax aide.

“Although a reform bill passed by the House is unlikely to be enacted, given the current political environment,” he said, “it will certainly provide a reference point for future fundamental tax reform discussions.”

Benton Ives contributed to this story.