I’ve been sitting on this post for a long time. Mainly, I didn’t want to call the election too early; I wanted the democratic process to play out and run its course.

At this point, though, the reality is undeniable.

I know a lot of Clinton supporters, and they’re all great people. Smart, engaged, passionate, hard-working Democrats through-and-through. And I know the situation they’re in—I know what it feels like to know that your candidate is losing. I know what it’s like to dig your heels in, to vow to stay in to the bitter end, to sit and wait for every last single vote to be counted and until every last bit of hope is gone.

But it’s time. It’s time to face the facts and acknowledge that Hillary Clinton will not be the Democratic nominee. It’s a painful realization—it would be painful for me if I had to acknowledge that Obama would not be the nominee—but it’s necessary. We have to do this.

Let’s look at how Clinton could—or could not—become the nominee.

(All delegate calculations use Slate’s Delegate Calculator)

• Hillary Clinton wins enough pledged delegates to win the nomination, and thus the superdelegates won’t matter.

This outcome is impossible at this point. Even if Clinton wins every remaining primary with 100% of the vote, she’ll have 1821 pledged delegates to Obama’s 1413. No matter what, the superdelegates will end up choosing the nominee.

• Hillary Clinton wins enough pledged delegates to take the lead, and the superdelegates go along with the popular vote and give her the nomination.

Even if Clinton wins every remaining primary with 60% of the vote, she’ll still trail Obama by 42 pledged delegates. It’s obvious that Clinton won’t win every remaining primary, let alone with a 20% margin of victory.

And there’s Clinton’s problem. No matter how the rest of the primary turns out, she’ll still trail Obama in terms of pledged delegates.

Now, the superdelegates are free to vote how they please. But barring the massive, unprecedented collapse of the Obama campaign, they’re not going to throw her the nomination.

See, if they give the nomination to Obama, he’ll have a certain measure of legitimacy—he won the popular vote, which is why the superdelegates supported him. If the superdelegates were to give the nomination to Clinton, they would be directly contradicting the will of the Democratic electorate, and there would be a massive backlash. The superdelegates know this, and they’re going to do everything they can to avoid that backlash.

The argument that the superdelegates can give the nomination to the loser of the popular vote is inherently undemocratic. It assumes that the electorate are idiots, and that we need elites to protect us from selecting the ‘wrong’ candidate. We are the Democratic Party, and the heart of democracy is that the people decide, right or wrong.

Should Clinton drop out? Yes. She can’t win, and all she’s doing now is hurting Barack Obama and the Democratic Party. Yes, the long primary means that our base, our activists and our donors are more engaged than ever, and that we Democrats are paying attention to states that almost never get any attention. But those benefits will only go so far, and I think we’ve reached the limit. At this point, Clinton will have to retract a lot of her statements and eat a lot of crow once this is all said and done, and some of her attacks on Obama have left lasting damage.

Some people may allege that I’m saying PA, NC, KY and the other states who haven’t voted don’t matter. No, of course they matter—people voting, participating, and letting their voices be hears always matter. But what I am saying is that they won’t choose the nominee, just like no other state to date has chosen the nominee. That’s just a fact.

This has gone on long enough. Obama is the only one who has any realistic paths to the nomination; Clinton’s paths are all based on assumptions, unrealistic expectations, or outright ludicrous scenarios. It’s time for us to get together and focus our efforts on the real threat to America: John McCain and his supporters in the media.