Democrats and Planned Parenthood supporters say the 90-year-old group is audited regularly and publicly and that the probe is the latest Republican run at shutting it down.

At issue is whether American taxpayers are unwittingly underwriting elective abortions, in violation of federal law. Absolutely not, says Planned Parenthood. But congressional Republicans are not so sure.

Planned Parenthood, the nation's largest provider of abortions and an array of other health services, is at the center of the fight. Republicans portray the organization as primarily focused on performing abortions, and charge that taxpayer funds for family planning and other health care services indirectly subsidized that role. They've launched multiple efforts this year alone to bar federal money from the group as long as it provides abortions. The Planned Parenthood Federation of America — the formal name of the organization — says taxpayer money is strictly separated.