President Obama is expected to enlist the aid of major U.S. corporations in fighting long-term joblessness in an announcement in his State of the Union address Tuesday evening.

Xerox, Lockheed Martin and Procter & Gamble confirmed that they are among large companies participating in a White House pledge to not discriminate against the long-term unemployed when hiring.

The wall street journal reported the pledge Monday morning. It commits corporations to boosting the long-term unemployed by ensuring that they are not unfairly treated in companies' advertising or hiring decisions and improving their efforts to hire those out of work for long periods. The pledge does not appear to include any legally binding provisions.

A spokeswoman for Xerox told the Washington Examiner that "signing this pledge is affirming that long-held principle and demonstrating our support for any and all initiatives that break down the barriers around discrimination."

The White House in recent weeks has drawn attention to the difficulties facing the 3.9 million Americans who have been unsuccessfully looking for work for more than 26 weeks. After the 5-year-old emergency program for unemployment benefits extending after 26 weeks expired in December, the Obama administration and Democrats have pushed to renew it. Democrats on the House Ways and Means Committee estimate that 1.6 million jobless have lost out on benefits so far.

Obama economic adviser Jason Furman noted following January's jobs report that the long-term unemployment rate, at 2.5 percent, is twice as high as it has been when the extended unemployment benefits program was ended in past economic recoveries. That 2.5 percent rate is also disproportionately high given that the overall unemployment rate is 6.7 percent and falling.

Recent studies have shown some evidence of discrimination by employers against the long-term unemployed. A researcher at the Federal Reserve Bank of Boston, for example, sent businesses resumes that featured similar qualifications but different unemployment spells, and found a "strong distaste for applicants with long spells of non-employment."

Nevertheless, the ranks of the long-term unemployed have dropped significantly over the course of the recovery, from nearly 7 million in 2010. As hiring continues to slowly pick up, the long-term unemployment problem is also expected to abate.