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By Wolf Blitzer, CNN
(CNN) - It looks like the gloves are beginning to come off between Mitt Romney and Newt Gingrich. The two Republican presidential front-runners are starting to go after each other after trying to stay above the fray over the past many weeks and months.
This should not be surprising since they are in a fierce battle for the party’s nomination and the clock is ticking. Iowa, New Hampshire, South Carolina, Nevada and Florida are coming up quickly.
Gingrich had tried to focus his attention on President Barack Obama. That was also Romney’s strategy. For both candidates, that is clearly an easy target. It energizes the party’s base. They certainly will continue to blast the president and his record over the past three years. But simply railing against Obama is clearly no longer feasible.
Right now, the stakes are too high for Gingrich and Romney. They can almost smell the nomination, and they will do whatever it takes to win - within reason.
That means they have to not only speak positively about their own respective qualifications in making make their case, they also need to explain why the other contender is not so good.
And that explains why we are now hearing Romney mention that his experience mostly has been in the world of business; Gingrich, he says, has been mostly in Washington.
And Gingrich clearly has Romney in mind when he says that anyone who claims the former speaker once supported “amnesty” for illegal immigrants in the United States is spreading a “falsehood” that should disqualify that person from winning the party’s nomination.
Having covered presidential campaigns for a long time, I must say those are relatively polite exchanges.
But as we get closer to the caucuses and primaries, the language will heat up. It always does. I can assure you both campaigns’ opposition research departments are already working overtime.
Just recall the tensions that developed between Barack Obama and Hillary Clinton as their campaigns for the Democratic nomination continued four years ago.
One final note: As tough as the GOP primary fight will become, it will be nothing compared with what we can expect in the general election battle between Obama and his Republican challenger.
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