By Ted Hesson

WASHINGTON (Reuters) – Democrats will on Thursday formally introduce President Joe Biden’s sweeping immigration bill in Congress, a measure that would provide a path to U.S. citizenship for an estimated 11 million immigrants in the country illegally, but the proposal faces long odds to passage.

The bill would greatly increase both family-based and employment-based legal immigration and allow certain previously deported immigrants to apply to return for humanitarian reasons. Key elements of the bill were first unveiled in January.

The legislation, which is expected to be hundreds of pages long, takes an aggressive pro-immigration approach. It has not received public support from Republicans, making it unlikely that it will be enacted.

Democrats hold a majority in the House of Representatives, but the Senate is split 50-50, with Vice President Kamala Harris as the tie-breaking vote. Democrats would need to win over 10 Senate Republicans to avoid a “filibuster,” a procedural hurdle that can delay or block legislation from coming to a vote.

“We know the path forward will demand negotiations with others, but we are not going to make concessions out of the gate,” Senator Robert Menendez, who will be the lead sponsor of the bill in the Senate, said on a call with reporters. “We will never win an argument that we don’t have the courage to make.”

Menendez said he had spoken with some Republican senators who are interested in parts of the legislation, but declined to name the lawmakers. Democrats would consider any avenue to accomplish immigration reform, including using a procedural move to pass a bill in the Senate with only 51 votes, he added.

Democrats are simultaneously pushing ahead with several smaller-scale immigration bills, including a measure that would offer a path to citizenship to so-called “Dreamer” immigrants living in the United States illegally after entering as children.

“I salute the president for putting forth the legislation that he did,” House Majority Leader Nancy Pelosi said on Thursday during a separate news conference. “There are others that want to do piecemeal and that may be a good approach, too.”

Some Republican senators have already expressed opposition to major provisions of the Biden bill.

The criticism was echoed on Thursday by Heritage Action, the political wing of the conservative Heritage Foundation.

“This latest move would only further harm American workers already struggling from our health and economic national crises caused by the ongoing pandemic and our government’s response,” said Jessica Anderson, the organization’s executive director.

(Reporting by Ted Hesson in Washington; Additional reporting by Makini Brice in Washington; Editing by Ross Colvin, Aurora Ellis and Howard Goller)