It was the tweet heard round the world. Last Saturday, Sen. Chuck Grassley of Iowa, a regular user of Twitter, sent a message to President Obama, who was half a world away in Paris. In his Saturday radio address, the president had called on Congress to move quickly to pass health care legislation. This elicited a 134-character rocket from Grassley, a Republican, who tweeted his response at 6:37 a.m.: "Pres Obama you got nerve while u sightseeing in Paris to tell us 'time to deliver' on health care. We still on skedul/even workinWKEND."

When I talked to the senator this week, I asked him about exactly what set him off. "You people in TV always have these things on the bottom of your TV sets so we can keep up on the news," he said. "And I read across there three or four words, 'President says got to get this done, better get this done,' or something like that. And I had my Blackberry with me, and you know what came out of that."

Grassley's point was that the president, who has taken a hands-off approach to health care reform so far, "ought to know better" than to prod members of Congress, who have already been working on the legislation for months. "Since he has been sworn in office," said Grassley, "those of us working on this issue who have been in almost constant communication with him. He knows the calendar we set up. And we are working overtime to stay within that calendar." Grassley says he doesn't begrudge the president "having a vacation with his family, sightseeing in Paris. I would enjoy doing that with my grandchildren. But to say what he said, it did not need to be said. It did not help the cause, and I resented it."

Grassley resented it so much he sent a second tweet to the president. (Twitter allows only 140 characters, after all.) "Pres Obama while u sightseeing in Paris u said 'time to delivr on healthcare' When you are a 'hammer' u think evrything is NAIL I'm no NAIL"

Nail? Hammer? What's all that about?

"Tom Delay was known as a hammer because he was always trying to beat everybody over the head to get everything done just the way he wanted it," Grassley says. "Well, I interpreted the president's remarks about get the job done as hammering us. I wanted the president to know that he can hammer, but he ain't hammering this nail."

After Obama returned from Paris, he met with members of the Senate Finance Committee, of which Grassley is the top Republican member. The two (kind of) joked about the incident. "Well, he kind of smiled, and he says, 'You know, Chuck, I just thought there was a very good reason for me to go to Normandy.' And quite frankly there was a very good reason for him to go to Normandy, and it is even all right if he takes his kids on a sightseeing tour through Paris." But Grassley said the comment was uncalled for, "particularly when my staff and [Finance Committee Chairman Sen.] Baucus' staff were working day and night on Saturday and Sunday while he was walking around the promenade."

The debate over health care legislation will continue for several more months, so this won't be the last opportunity for Sen. Grassley and President Obama to exchange views. And though Obama typically prefers to conduct debates through speeches and other public remarks, maybe he can make an exception for the senator from Iowa and respond in just 140 characters. He does still have his Blackberry, after all. Maybe in August, while he's spending some vacation time with his family, he can take a moment to dash off a quick tweet: "@chuckgrassley thanks getting health care legislation out of the Finance Committee. Enjoy some time on the promenade."