By ANDRES OPPENHEIMER

Of all the challenges that presumptive Democratic presidential candidate Barack Obama will face to win the November elections, one of the biggest ones will be conquering the Hispanic vote.

It won't be easy.

Sen. Obama didn't do well with Latinos in the primary season, and he can't win the White House without their massive support.

While most Hispanics have traditionally voted Democratic and have flocked in record numbers to the Democratic Party in the recent primary elections -- courtesy of the Republican Party's increasingly harsh anti-immigration rhetoric -- much of the Latino vote went to Obama's rival for the Democratic nomination, Sen. Hillary Clinton.

Clinton beat Obama among Hispanics by 73 to 27 percent in New York, by 69 to 30 percent in California, by 68 to 32 percent in Texas, by 70 to 30 percent in New Jersey, and by 61 to 35 percent in Florida. Obama beat Clinton among Hispanics in his home state of Illinois and others, but they were few and far between.

Pollsters say that Obama's biggest weakness within the Latino community lies with foreign-born Hispanics, who make up nearly half of the estimated 13 million registered Hispanic voters.

All of this poses a huge challenge to Obama.

To win in November, he needs not only to win the Hispanic vote in key swing states -- such as Florida, New Mexico and Colorado -- but to do so by larger-than-usual margins.

FOUR CRUCIAL STATES

''The Latino vote will be more important than ever in this year's election,'' says Sergio Bendixen, a Democratic pollster. ``The election may be decided by Florida, New Mexico, Colorado and Nevada, where the Hispanic vote can decide who wins in those states.''

According to Bendixen, Obama needs to win the Hispanic vote by a margin of more than 55 percent in Florida, and by more than 65 percent in New Mexico, Colorado and Nevada. And if likely Republican nominee Sen. John McCain gives the Democrats a fight in New Jersey, California and Pennsylvania, Obama will need to do even better than that in these states.

Will Obama be able to do that? A poll released last week by Democracy Corps, the James Carville-Stan Greenberg group, shows that Obama beats McCain among Hispanics by 60 percent to 34 percent. A Gallup poll also released last week shows Obama is ahead among Hispanics by 62 percent to 29 percent.

Many Democratic strategists are hailing these figures as a good sign for Obama. A new report by the New Democrat Network shows that the number of Hispanic voters in this year's primary season has tripled since the 2004 primaries, and that the Democratic party has increased its share of Hispanic voters by 66 percent over the past four years.

''The latest national polls show that Obama is showing surprising strength among Latino voters, given the weakness that he showed in the primaries,'' says NDN president Simon Rosenberg. ``There is a new dynamic in the Hispanic electorate: we are seeing a very high level of civic participation, and a big swing toward the Democrats.''

BUSH AS YARDSTICK

Republicans counter that McCain needs to get close to the 38 to 40 percent of the Hispanic vote that was won by President Bush in the past two elections, and that he is not too far from that goal.

''This contest is only beginning and we have five months to remind Hispanics that John McCain has always stood by us and taken political risks for our community, whereas Obama has little if any record of supporting the community,'' said Ana Navarro, co-chair of McCain's Hispanic Advisory Council. ``The latest polls are positive for McCain, and a good foundation to build on.''

My opinion: Obama will try to win Hispanic voters by focusing on issues that most affect them, such as the economy, universal healthcare, and the war in Iraq. McCain will most likely engage in a negative campaign to stress Obama's lack of experience, and depict him as weak on national security in an increasingly dangerous world.

Obama will have to go out of his way to win the Hispanic vote by a landslide. The virtual democratic nominee, who has never been to Latin America, told me in a recent interview that he plans to visit Mexico before the November elections. That's great, but he will have to do much more than that.