Expanding on comments he made on Sunday's edition of All Things Considered a key Senate Democrat said today he thinks there are enough "aye" votes in the Senate to include make the so-called public option as part of any health care overhaul legislation.

Sen. Tom Harkin, D-Iowa, said on radio's The Bill Press Show that he thinks there are the 60 votes to avoid a Senate filibuster on the legislation and that he has "polled senators and the vast majority of Democrats, maybe approaching 50, are for a public option. Why shouldn't we have a public option? We have the votes." (Audio of Harkin's interview with Press is posted here.)

The "public option" is a government-backed health care plan that would serve as an alternative to private plans. President Barack Obama and many fellow Democrats believe such an option would promote competition. Some Democrats and most Republican lawmakers say the option could have an unfair advantage over private plans and have raised the specter of "government-run" health care.

Update at 2:57 p.m. ET: Harkin had already discounted the likelihood that the Senate Finance Committee's version of a health care overhaul would not include the public option — and that committee did indeed just vote 15-8 NOT to include the public option in its legislation.

For much more on the health care debate, and other health-related issues, check the NPR Health Blog.

Here's the interview Harkin did with ATC's Guy Raz:

(h/t: The Hill's Blog Briefing Room.)