TVNewser is hearing one of the reasons Sen. Hillary Clinton may not accept CBS's invitation to the North Carolina debate is because it's planned for April 19, the first night of Passover. Political insiders tell us it could also be tactical: that agreeing to a North Carolina debate would de-emphasize the importance of Pennsylvania, just three days before PA voters go to the polls. Which is exactly why Sen. Obama did agree to it, figures the insider.

If it does go forward, Katie Couric will moderate the debate along with Bob Schieffer. It would be CBS' first debate this primary season.

Meanwhile, ABC News is going ahead with plans for an Obama-Clinton debate set for Wednesday, April 16 in Philadelphia. Both candidates have agreed to that debate. Charlie Gibson is expected to moderate. It would be Gibson's third time moderating this primary season.

> More from an insider: April 19 was just one of several dates being considered for the CBS debate. So it could happen, but perhaps on another day.