Washington ? President Bush can go to war with Iraq without Britain’s Tony Blair. He can go to war without Jordan’s King Abdullah. He can even go to war without Saudi Arabia’s King Fahd. But he can’t go to war without Indiana’s Dick Lugar.

Richard G. Lugar is an introverted intellectual whose impulses have a very unusual effect on others in Washington. They make people actually listen and they have an especially jarring effect on his Democratic rivals. Lugar is, by ideological inclination, the center of gravity of Capitol Hill. But his impact comes from more than that. His determination and diligence also make him the congressional center of gravitas.

His colleagues shout. He whispers. And right now Lugar is whispering above the din: We’re not ready to go to war with Iraq.

Not yet, anyway. “I think we can be ready,” he said in a conversation the other morning. “There are, I suspect, substantial military plans already developed, some sprinkled out in the media, some not. But until we run through the traps and see what we can do, we’re not ready. We have to have the support of all the major countries, not just the ones that surround Iraq but also Russia, and we have to have some acquiescence from the Chinese.”

Lugar has spent his time in the capital outliving one terrible distinction (he was Richard Nixon’s favorite mayor) and creating one luminous distinction of his own (he is the only man known to have turned down an invitation to a state dinner at the White House because it was his wife’s bowling night).

Now he is bringing special credibility to the Iraq debate. A decade ago, he battled a reluctant Bush administration to seek congressional approval for the Gulf War. The current president’s father resisted but was glad he had that formal authorization in his back pocket. A half-dozen years ago Lugar ran for president he was the Republican Adlai E. Stevenson, without the riotous sense of humor and intuitive populist touch and was ridiculed by a lot of smart people who chortled over how Lugar was stumping in Iowa and New Hampshire on the two biggest loser issues in presidential-campaign history. (Those surefire snoozers were terrorism and the lax controls on nuclear materials. This doesn’t seem quite so uproarious now.)

This steamy summer, however, people are listening. This is what Lugar is saying: The current President Bush should get congressional authorization for military action against Iraq. The administration has to prepare the nation for warfare and, just as important, it has to prepare the nation for what peace in Iraq might look like (and how much it will cost). The American outreach before the war must take account of Iraqi debts owed to Russia and Iraqi oil concessions owned by France.

“I haven’t heard this kind of planning illuminated in any form, or even suggested,” Lugar said.

Now he might. Ordinarily Lugar is the sort of legislator whose work is seen in the fine print of Washington, the legislative equivalent of the baseball box score. But this is an era where the fine print matters. Just this month, for example, he and Sen. Joseph R. Biden Jr., the Delaware Democrat who heads the Senate Foreign Relations Committee, teamed up on (and passed) a little-noticed amendment that will provide funds to eliminate 1.7 million chemical weapons shells in Russia.

Lugar’s critique of U.S. readiness in Iraq is sending ripples throughout Washington. “Lugar is very important in this,” said Sen. John F. Kerry, a Democrat of Massachusetts and a member of the Foreign Relations Committee.

The axis of evil has spawned an axis of debate that, in Republican circles, runs the gamut from former Defense Secretary Caspar W. Weinberger to Sen. Lugar. Weinberger’s view was deftly captured in the opening statement of his testimony in the Senate hearings on Iraq last week: “If we go in alone and remove Saddam Hussein, we’ll find that success has many allies.”

Nice line. But Lugar thinks it is more complicated than that.

“But how do you find the (weapons) laboratories?” Lugar asked in a conversation. “What do you do after you vanquish the Iraqi military? The Weinberger testimony may represent the common feeling that it’s a messy business but somebody’s got to do it but even if we are successful, it is not clear to me how it could be done and it is not clear to me what happens the day after. Even if there were excellent plans in the Pentagon for military success, there need to be correspondingly good plans in the Treasury Department and the Commerce Department. I don’t see that yet.

“We were being asked,” he went on, “to slide into this situation or to accept the fact that somebody has thought of all of this. I don’t think they have.”

All the world is looking for signs of Washington’s readiness. There are accounts floating around of decisions made, or almost made, and of combat vehicles with the leafy camouflage of the Cold War and Vietnam being replaced with the sandy camouflage of desert warfare. Some of this may actually even be true. But, this, too, is true: The most dependable indicator of American intentions in Iraq won’t be leaked reports from the Pentagon but public statements from Richard Lugar, one-time member of the Indianapolis school board.