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A longtime Washington insider known for remaining level-headed in moments of crisis, Mr. Lew is generally respected on both sides of the aisle on Capitol Hill, so his confirmation wasn’t expected to be particularly bruising.

But Wednesday, Sen. Jeff Sessions of Alabama, the top Republican on the Senate Budget Committee, said he will lead a charge to try to block Mr. Lew’s prospective nomination to become Treasury secretary.

Mr. Obama is expected to announce Thursday his decision to tap Mr. Lew to take over for outgoing Treasury Secretary Timothy F. Geithner.

Mr. Sessions told The Washington Times that Mr. Lew blatantly misled Congress about administration plans to reduce the national debt and “must never be secretary of Treasury.”

Two years ago, while serving as Mr. Obama’s budget director, Mr. Lew told Congress that the president’s budget, which he had crafted, would not add to the national debt.

Mr. Sessions called the claim so “outrageous and false” that it alone should disqualify Mr. Lew from the key Cabinet post.

The Senate Finance Committee will hold the hearings, so Mr. Sessions will not have a chance to question Mr. Lew directly. Instead, according to Senate Republican aides, he plans to voice his concerns about the nomination if and when it hits the floor.

The timing of the Treasury nomination is critical because Mr. Lew is expected to play a central role in several budget debates.

Congress needs to raise the debt ceiling by late February or early March or face defaulting on its debts. But brinkmanship over the last debt-ceiling debate in 2011 led to a downgrade in the U.S. credit rating, and the major credit ratings agencies have warned that another downgrade is possible this spring.

Undaunted, Republicans are gearing up for a major battle over the increasing the nation’s borrowing limit as a way to extract concessions from Democrats on spending cuts.

Congress and the Obama administration face another deadline for budget cuts. The fiscal cliff deal only served to delay by two months an automatic “sequestration” agreed to in an earlier deficit-and-debt deal, which would result in across-the-board spending cuts to defense and domestic programs.