By Wolf Blitzer, CNN

(CNN) – Vice President Joe Biden is now willing to name names in going after Mitt Romney, Rick Santorum and Newt Gingrich. President Obama is now increasingly willing to go after them, but he’s still avoiding naming names.

Here’s how he criticized Romney on health care mandates this week in an interview with Public Radio International:

“We designed a program that actually previously had support of Republicans, including the person who may end up being the Republican standard bearer and is now pretending like he came up with something different.”

President Obama is certainly in full campaign mode, raising lots of money at fundraising events across the country and speaking in key battleground states like Ohio, but he also wants to take the high road. He’s leaving the harder hitting campaign rhetoric to Biden and his other aides and supporters.

That is the way it is for an incumbent president. That is also smart for now.

I remember covering President Bill Clinton when he was up for re-election 1996 and President George Bush when he was up for re-election in 2004. At this stage in the process, they were both wisely seeking to take full advantage of being in the White House, acting presidential and leaving the more blatant political activity to their supporters.

The so-called Rose Garden strategy can be effective.

But at some point, the presidential gloves really come off. That will certainly happen by the time of the Democratic Convention in Charlotte, North Carolina, in early September. But I suspect it could happen a lot earlier.

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