With President Bush expected to veto a bipartisan stem-cell research bill today, Senate Democrats have decided to try to force through a narrower expansion of the controversial research on human embryos by tacking it onto an appropriations bill.

According to Senate Democratic sources, Sens. Tom Harkin (D-Iowa) and Arlen Specter (R-Pa.), the chairman and ranking member, respectively, of the Senate Appropriations subcommittee on Labor, Health and Human Services, Education and related agencies, decided today to add the provision to their fiscal 2008 spending bill, which will be considered by the full Appropriations panel on Thursday.

The Labor-HHS bill already is on the short list of appropriations measures likely to be vetoed by Bush, who is expected to return as many as nine of the 12 annual spending bills to Congress this year because of the White House’s opposition to the Democrats’ higher spending limits.

But one Senate Democratic source said the addition of the stem-cell provision will help divert attention from the price tag of the bill, which is expected to be far more expensive than the president requested.

Rather than allowing federal funding for all kinds of embryonic stem-cell research, as the soon-to-be vetoed bill would do, Harkin and Specter simply would expand the number of stem-cell lines that researchers could use. While Bush issued an executive order his first year in office limiting federal funding to research only on lines that were derived prior to Aug. 9, 2001, the Harkin-Specter language would allow funding for lines derived before June 15, 2007.

Senate Democratic sources cautioned that the provision is not intended to replace the free-standing stem-cell bill, but is intended as a potential compromise measure.