Neutral Iowa Sen. Harkin tells CNN a handful of the 17 undeclared Senate supers are meeting on Capitol Hill Monday to "talk" about getting behind a candidate.
Harkin adds he won't declare who he's for until the polls close Tuesday.
NBC News: At least 34 House members tell the network they're planning to endorse Obama by Wednesday.
Plus: Uncommitted Pennsylvania Rep. Altmire tells the AP Obama is pushing for supers to endorse during the day Tuesday so he'll have enough delegates to declare victory that evening.
"He apparently is telling people that he has the numbers, and that's what's going to happen, at which point it would become moot what the rest of us do."
More: MSNBC says Obama has invited 28 Democratic governors to meet in Chicago June 16 to help plan for the general.
