The Democratic Senatorial Campaign Committee (DSCC) is spending money on Sen. Arlen Specter's (D-Pa.) increasingly difficult primary.

As poll numbers show Rep. Joe Sestak (D-Pa.) catching up to the senator, a source confirms the DSCC is spending coordinated funds for Specter. The spending was first reported by my former colleague, Reid Wilson.

Coordinated funds differ from most party spending in that the committee can use the money to work with the candidate and supplement his or her ad buys. But such funds are capped at a certain amount depending on the race — $855,400 in the Pennsylvania Senate race — while non-coordinated or independent expenditure funds can be spent in unlimited amounts.

The DSCC has openly backed Specter over Sestak, but actually spending money on the race is a more unusual step. Specter is also getting an assist from President Barack ObamaBarack Hussein ObamaGOP group makes late play in Iowa seat once seen as lost Chance the Rapper works as Lyft driver to raise money for Chicago schools Americans are safer from terrorism, but new threats are arising MORE, who has cut a radio ad for him.

The committee spending has already led the National Republican Senatorial Committee (NRSC) to ask whether the DSCC will do something similar for Sens. Michael BennetMichael Farrand BennetEagles player sits out national anthem Trump administration denied it has ‘secret’ committee seeking negative information on marijuana: report Overnight Health Care: Senators target surprise medical bills | Group looks to allow Medicaid funds for substance abuse programs | FDA launches anti-vaping campaign for teens MORE (D-Colo.) and Blanche Lincoln (D-Ark.), who both face primaries as well.