A spate of bills to cut federal red tape and otherwise make it easier to get aid to victims of Hurricane Katrina (search) has hit a slow patch as lawmakers wrestle over how to shape their response.

Congress zipped through bills providing $62 billion in emergency aid to hurricane victims (search) but the broader legislative response is a work in progress.

Included in this second phase are proposals to provide Medicaid (search) health benefits to those made homeless by Katrina, lift work rules for welfare recipients, and implement tax changes to help hurricane victims and charitable donors. More comprehensive bills are to follow.

Republicans are starting to voice complaints that Democrats are seeking to seize upon the tragedy to pass more ambitious legislation than they otherwise could expect to achieve in the GOP-dominated Congress.

"In some instances, (Democrats are) trying to up the ante and use this crisis to accomplish goals that maybe they wouldn't have otherwise been able to accomplish without a natural disaster," Senate Finance Committee Chairman Charles Grassley, R-Iowa, said. Grassley is at the center of the storm as he negotiates over taxes, welfare and Medicaid.

For example, a House-passed bill to temporarily ease rules requiring that welfare recipients work 30 hours a week for their benefits and extend the welfare (search) program is still pending before the Senate, despite a big push by Majority Leader Bill Frist, R-Tenn., to clear it for President Bush's signature. Democrats are pressing for a more generous approach.

For their part, outgunned House Democrats have settled on a far-reaching Katrina response plan, including housing vouchers, increases in unemployment insurance payments and full Medicaid coverage for hurricane victims.

Grassley has formally introduced a bipartisan tax break plan costing up to $7 billion that would let hurricane victims tap their retirement accounts, assist businesses and encourage charitable donations. A House plan is still taking shape.

Moving any bill quickly through the notoriously balky Senate requires bipartisan negotiations among a host of political players, so it's not unusual to hit snags.

Bush, meanwhile, facing sharp criticism and the lowest approval ratings of his presidency, scheduled a speech to the nation from Louisiana for Thursday evening. It will be his fourth trip to the devastated Gulf Coast since the storm struck two weeks ago.

The president on Tuesday acknowledged again the inadequacy of the federal response and for the first time assumed personal responsibility for its failings.

"And to the extent that the federal government didn't fully do its job right, I take responsibility," he said. "I want to know what went right and what went wrong."

On Wednesday, Congress was to begin investigating the government's readiness and response to Katrina at a Senate Homeland Security Committee hearing. Committee Chairwoman Susan Collins, R-Maine, said the inquiry would investigate the sluggish response at all levels of government.

"It's going to be an in-depth, extensive review," Collins said.

Democrats continue to press for an independent, bipartisan panel modeled after the Sept. 11 Commission and they say congressional inquiries should not be controlled by Republicans.

"The only thing I will agree to ... is the same number of Democrats on the committee as Republicans and both Democrats and Republicans have to sign off on subpoenas," said Senate Minority Leader Harry Reid, D-Nev. "Other than that, they're wasting their time talking to me."

Senate Republicans killed the first of several attempts by Democrats to seize on Katrina to add disaster-related funds to a pending spending bill, a $48.9 billion measure funding the budgets of the departments of Commerce and Justice.

By a 56-41 vote, Republicans defeated a bid by Sen. Joseph Biden, D-Del., to add $700 million to the spending bill for grants to local governments to hire police officers and another $300 million for better communications equipment for local first responders.

Votes were expected Wednesday on other Democratic proposals to the spending bill, including a plan by Sen. Hillary Clinton, D-N.Y., to establish an independent, bipartisan Katrina Commission to investigate federal, state and local government response to the catastrophe. A vote also was set Wednesday on a $5 billion upgrade of communications equipment that would make it easier for police, firefighters and other law enforcement authorities to talk to each other during emergencies.