Under pressure from progressive groups to reject Wall Street influence, three more Senate Democrats yesterday turned against the nomination of Antonio Weiss for a senior post at the U.S. Treasury Department.

President Barack Obama’s choice of Weiss, an investment banker at Lazard Ltd. (LAZ), has put him at the center of an ideological fight within the Democratic Party over the finance industry’s clout in Washington.

The attacks are coming from Democrats who say the Obama administration relies too much on Wall Street veterans to fill important regulatory posts. They are criticizing Weiss, in particular, for his role in engineering tax-lowering inversion deals for U.S. companies.

The opposition yesterday from Joe Manchin of West Virginia, Jeanne Shaheen of New Hampshire and Al Franken of Minnesota further complicates the nomination for the administration and Democratic leaders. After defending Weiss’s Democratic bona fides and accepting his campaign contributions, they’ll have to turn to Republicans to get him into office.

“This fits the administration’s pattern of choosing Wall Street insiders to senior policy positions instead of those with strong consumer protection or community bank and credit union experience,” Manchin said on the Senate floor yesterday.

Obama nominated Weiss last month to become undersecretary for domestic finance. If confirmed, he would be responsible for coordinating policies on banking, capital markets and regulation and managing the issuance of the country’s debt.