HALPERIN'S TAKE: Seven Reasons Why the Kennedy Endorsement is a Big Deal

While endorsements don't usually matter much, Edward Kennedy's does because:

1. He has a huge following with Hispanics, a big deal in California and other Super Tuesday states, and one of Obama's weaknesses.

2. The symbolic Kennedy family thing -- the ultimate message of change, viability, Democratic legitimacy, and youthful excitement.

3. The national press will be obsessed with the story for days and days to come, with no downside for Obama; the local press coverage when Kennedy travels for Obama will be ginormous.

4. It sends a message to other senators and superdelegates that it is OK to be for Obama -- they don't have to be afraid of the Clintons.

5. He has a huge following among working-class, traditional Democrats, one of Obama's weaknesses.

6. He has a huge following among union households, another of Obama's weaknesses.

7. He has a huge following among older Democrats, yet another of Obama's weaknesses.