It’s time for Democrats to be careful.

We have the two strongest candidates to run for president since Bill Clinton.

We have a race that is not likely to end until June, at the earliest.

We have a party that is desperate to defeat the Republicans and change the course of the country’s future on both foreign and domestic policy and a country that supports change and overwhelmingly believes that the country is on the wrong track.

The Republican battle is over, and the Democratic race is still heating up.

The conventional wisdom is that the sooner you win your party’s nomination, the more it is worth.

The conventional wisdom is that the more hard-fought the primary campaign, the more divided the party will be in the end.

That’s why Democrats need to be careful. We need to be careful to remember that our two candidates agree on far more than they disagree, that the opponent is John McCain and not Barack Obama or Hillary Clinton.

From the beginning, I’ve been arguing that this race would be good for the Democratic nominee, that Hillary Clinton or Barack Obama would be stronger candidates for having defeated the other.

I also said that it would give Obama the chance he needed to grow as a candidate and prove himself a leader and that it would give Hillary Clinton the opportunity she needs to take on the misconceptions and caricatures that have produced her high negatives and taken her from front-runner to underdog.

I still believe that.

But I’d be lying if I didn’t admit that I’m getting a little bit nervous.

I’m not nervous that Clinton is taking on Obama and Obama is taking on Clinton. Believe me, I have faced the Republicans at their fiercest, and nothing these Democrats do to each other begins to approach it.

I’m not worried the Republicans are going to use the Democrats’ lines against the future nominee. The longer this goes on, the more likely it is that these two Democrats will end up on a ticket together, and whatever each has said about each other is nothing compared to the "voodoo economics," which didn’t cost George Bush the first the second spot on the Reagan ticket or Reagan the election in the fall.

I can even make the case that, conventional wisdom notwithstanding, the reality is that with the Republican nomination locked up, McCain is about to fade from the news, be missing from the front pages, while the country devotes its attention exclusively to the race between two Democrats who ultimately will be stronger for the scrutiny and, potentially, viewed as more qualified because of the attention.

No, what I’m worried about is what’s happening at the grassroots level among Democrats who support one or the other candidate and are coming to like their own candidate more, and the other one (and their supporters) less, the longer this goes on.

I remember what it was like in 1980, when the Kennedy and Carter people still were barely speaking to each other within days of the general election. That was when I — former Supreme Court law clerk, issues director and platform coordinator — ended up running the Election Day operation in Dade County, Fla., not because I knew anything about moving millions of voters to the polls but because I was a Kennedy person working for Carter and, therefore, trustworthy.

That’s what Democrats can’t afford.

I went to brunch the other day with some very close friends. One was an Obama supporter. I can honestly say that some of my best friends are Obama supporters, and up to now it hasn’t been so much of a problem.

My friend Dolores occasionally gets my goat for something I write, but we’re all still on the same team. At brunch, another close friend wouldn't let me off the hook. You’d think we were on television arguing instead of at brunch celebrating a close friend’s birthday.

His passion would have been admirable, except that after a few months of just being passionate, it’s getting harder and harder for some Democrats not to feel frustrated with the obstacle to their passion.

My Clinton friends are really no different. It used to be that they would just say they preferred Obama. Lately, it’s getting stronger. They’re getting mad.

Clinton has no reason to drop out after her impressive showing Tuesday night. Obama has no reason to let up, given his lead in delegates. This one is going to go on. Even as the race heats up, the folks on the sidelines need to chill. It’s a long way until November, and the Kennedy-Carter split is the memory no one wants to relive.

Susan Estrich is the Robert Kingsley Professor of Law and Political Science at the University of Southern California. She was Professor of Law at Harvard Law School and the first woman President of the Harvard Law Review. She is a columnist for Creators Syndicate and has written for USA Today and the Los Angeles Times.

Estrich's books include the just published "Soulless," "The Case for Hillary Clinton," "How to Get Into Law School," "Sex & Power," "Real Rape," "Getting Away with Murder: How Politics Is Destroying the Criminal Justice System" and "Making the Case for Yourself: A Diet Book for Smart Women."

She served as campaign manager for Michael Dukakis' presidential bid, becoming the first woman to head a U.S. presidential campaign. Estrich appears regularly on the FOX News Channel, in addition to writing the "Blue Streak" column for

Susan Estrich is currently the Robert Kingsley Professor of Law and Political Science at the University of Southern California and a member of the Board of Contributors of USA Today. She writes the "Portia" column for American Lawyer Media and is a contributing editor of The Los Angeles Times. She was appointed by the president to serve on the National Holocaust Council and by the mayor of the City of Los Angeles to serve on that city's Ethics Commission. A woman of firsts, she was the first woman president of the Harvard Law Review and the first woman to head a national presidential campaign (Dukakis). Estrich is committed to paving the way for women to assume positions of leadership. Books by Estrich include "Real Rape," "Getting Away with Murder: How Politics is Destroying the Criminal Justice System" and "Dealing with Dangerous Offenders." Her book "Making the Case for Yourself: A Diet Book for Smart Women," is a departure from her other works, encouraging women to take care of themselves by engaging the mind to fight for a healthy body. Her latest book, The Los Angeles Times bestseller, "Sex & Power," takes an impassioned look at the division of power between men and women in the American workforce, proving that the idea of gender equality is still just an idea.