Read closely, and you will notice a difference in the tone of the recent superdelegate endorsements for Sen. Barack Obama for president and those for Sen. Hillary Rodham Clinton.

Among the endorsements announced after the Indiana and North Carolina primaries, Obama’s superdelegates leave no doubt about their enthusiasm. Their statements call him a man of vision, an exceptional leader, possibly Superman, etc. “We can build a consensus that will last a generation,” said Rep. Brad Miller, D-N.C.

Clinton’s newest superdelegates just say they’d vote for her at the Democratic convention if the fight lasts that long, and only because their districts voted for her.

For example, Clinton said last week that she was pleased to receive an endorsement from Rep. Heath Shuler, a North Carolina Democrat.

Not so fast, Shuler’s office says. He has pledged to vote for her at the convention if it becomes necessary, since she won his district in last week’s primaries, said spokesman Andrew Whalen. However, he’s not singing her praises or performing any surrogate duties.

“I think there’s a difference between pledging a superdelegate vote and making an endorsement,” Whalen said.

Likewise, Rep. Brad Ellsworth, D-Ind., has taken issue with news reports describing him as an endorser. He, too, said he would if necessary cast his vote for the candidate who won his district, said spokeswoman Liz Farrar — and that happens to be Clinton.

But that’s different from putting out gushing statements or making speeches on Clinton’s behalf, she said.

Just semantics? Maybe, but at this point Clinton could probably use a bit more enthusiasm.

Even Rep. Christopher Carney, whose support Clinton announced May 9, chose his words carefully. “Pennsylvania’s 10th District overwhelmingly chose Senator Clinton in the Pennsylvania primary and I will respect their decision,” he said in his statement.