Hillary Clinton had a window of opportunity to stop or slow her opponent's momentum.

And Barack Obama's window, through which so many see whatever good things they want, offered Clinton maybe one last shot at ruining the view. The result? Her window's closing. His still is open.

For as she fights to keep her campaign from sliding away, Clinton failed to slow the slide. She gave Democratic voters no solid, concrete reason why not to vote for Obama.

The 20th and maybe last Democratic presidential debate of the season at Cleveland State University, aired on MSNBC-TV, did not provide the boost she needs.

Oh, she tussled with him over details of health care and NAFTA and more, but it was mostly rehash from past debates.

So much so that the "live" audience seemed anything but.

The only time it reacted was after a discussion of Nation of Islam Minister Louis Farrakhan's stated support for Obama got batted around by both candidates until Obama agreed with Clinton that it should be "rejected" and "denounced." On this a campaign might turn?

Other highlights included Clinton whining that she often gets the first question in debates and referring to a "Saturday Night Live" skit in which Obama is kid-gloved by the media.

Senator, it's comedy.

We got the Clinton laugh "twice" over a piece of tape in which she pokes fun at Obama's audacity of hope, to which he showed no offense; in fact, he said she "showed some good humor."

And she drew a short snort from Obama for saying, "He basically threatened to bomb Pakistan." He later said he hadn't.

Clinton's overall effort was scattered, ill-focused.

There was no hint of last month's connect-with-average-voters-in-New-Hampshire Hillary. But there was some of last week's "I-am-absolutely-honored"-to-be-with-Obama-in-Texas Hillary.

And, of course, no reference to the I-might-protest MSNBC since it was MSNBCers saying she had gotten where she is because of her husband's infidelity and because she had "pimped out" daughter Chelsea for support.

Clinton needed something to slow, even a bit, the spreading appeal of Obama, who leads her in national polls, is now ahead in some Texas polls and is closing fast in Ohio polls.

Both those states have key primaries Tuesday. Ohio, where Clinton leads in polls, is much like Pennsylvania in its basic demographics. With roughly the same population, it's slightly less educated (21.1 percent have college degrees; in PA it's 22.4 percent; both below the national average), just about as white (85 percent vs. 86 percent) and only slightly blacker (12 percent vs. 11 percent).

And Cleveland State professor Richard Perloff, director of the university's school of communications, tells me Ohio might not be susceptible to Obama's oratorical charms.

"Ohio's one of the states hardest hit by the home mortgage and predatory-lending crisis," he says, "and with 200,000 lost man-ufacturing jobs, symbolic themes don't resonate as much here."

Maybe so. But with or without Ohio, Clinton's on the ropes.

And the thing is? I don't think it's her. I don't think she's done much wrong. He's just a better candidate, better able to shape a campaign to fit cleanly into the window American voters opened. The question is whether it stays open and, if so, for how long?

Last night, I didn't see or hear anything that will close it, cloud it or crash through it soon. *