At the moment, Sen. Hillary Clinton clearly trails Sen. Barack Obama in the camaign for the Democratic presidential nomination.  But how long does she maintain a plausible path to the nomination?

At OpenLeft Chris Bowers breaks out six delegate counts, arguing that unlikely that either campaign will concede as long as it leads in at least one of these six counts.  Conversely, the beginning of the end is marked when a candidate leads in all six counts.  Bowers then reaches the following conclusion:

Obama needs a net gain of 61 delegates of any sort, while Clinton needs a net gain of 87 among pledged delegates and a net gain of zero among superdelegates. Pennsylvania also appears to be a potentially decisive, and inevitable, showdown.

His second conclusion builds upon the first:

My best guess is that as long as Clinton wins either Ohio or Texas, her campaign will continue on to Pennsylvania no matter what. Even if Obama reaches his key number of a net gain of 61 by March 15th, it is unlikely that he will do so by a margin that Pennsylvania would be unable to reverse. As such, there is no reason for Clinton to not at least try Pennsylvania, given the long break and that the demographics there are reasonably favorable to her (very old, not very creative class, and a closed primary).

I would also suggest that the fourth count Bowers gives — “Pledged plus super delegates, no Florida or Michigan” — may be the key count, as the disputes regarding Florida and Michigan may be the last to be resolved, or rendered moot if this count is decisive.  Under this count, Obama needs to collect 48.3 % of the remaining delegates, while Clinton would need to collect 52.6% of the remaining delegates.  These percentages are similar in four of the six counts.  A 4.3% margin seems manageable for Clinton through Pennsylvania.  If maintained, it would likely keep superdelegates from stampeding to Obama.  Clinton tthen could have a shot at running the trail all the way to Puerto Rico.

However, Clinton has to use that time to change the current dynamic of the race if she is to retake a lead and win the nomination. While Democratic strategists say Clinton retains a path to victory, she has little margin for error.  Most believe she will have to go negative to bring Obama back to Earth.  But their additional suggestions are intriguing.

Democratic pollster Paul Maslin suggests “She’s got to say, ‘I’m winning the hearts and minds of the middle-class Democrats; they’re the ones who are going to decide this race in the fall.’” I have recently suggested that Hillary start remembering the forgotten middle-class, which would serve several purposes.  It would provide a focus to her campaign.  It would match the demographics of must-win states like Ohio and Pennsylvania.  It would provide an opening to engage Obama at the level of policy, which is his weaker suit (as compared to the “vision thing”).

Democratic political consultant Dan Gerstein has an interesting take on whether going negative would really be going negative:

“The best thing she can do is either discredit Obama or raise doubts about him.

“I hate to say it, but in certain respects, it’s using the Bush strategy against Kerry against Obama and raising doubts about his willingness to use force to keep the country safe,” he said.

“The Obama people and the pacifists will scream ‘scare tactics.’ But for a lot of people, that’s not scare tactics — they care about national security and the commander in chief responsibility.”

It is somewhat remarkable that Hillary rarely sells herself as the best “commander in chief” and rarely directly compares herself to Obama in this way.  It is remarkable because when she was elected, she aggressively lobbied to get a seat on the Senate Armed Services Committee – presumably to gain a credential, if not the expertise, with which to argue that she would make a better CinC than her rivals for the nomination.

It is also remarkable because – even among Democrats who overwhelmingly oppose the invasion of Iraq – Hillary Clinton always does better on the exit poll question of who is best qualified to be commander in chief than her vote totals tend to show. 

For example, in states like Connecticut, Delaware and Missouri, she beat Obama on the CinC question while losing the total vote.  Even in states where she was trounced by Obama, Hillary’s margin on the CinC question is generally much better.  For example, in Maryland, Obama won 60-37% overall, but won the CinC question by 50-46%.  In Lousiana, Obama won 57-36%, but won the CinC question by 52%-44%.  Even in Georgia, where Obama won 67-31%, he won the CinC question by only 56%-35%. 

In a system of proportional allocation of delegates, selling herself more on the CinC issue might at least have cut Obama’s margin of victory to the extent possible, given the identity politics at work.  She may even have been able to sell herself as CinC without directly attacking Obama on the question, but she probably cannot be subtle now.

Update:  Allahpundit asks how Clinton exploits the CinC issue without Obama throwing Iraq back in her face.  My answer — such as it is — is at HotAir.