Britain's agile leader launched a new strategy today to solve Britain's most intractable political problem -- Northern Ireland -- and the betting was that Prime Minister Tony Blair might pull it off.

In an address to the House of Commons, Blair said he will work continuously over the next 10 days to sell his latest proposal for reviving the peace process in Northern Ireland. He reportedly has crafted a plan to do that using a combination of sticks and carrots -- plus a good deal of political theater.

Blair and his counterpart from the Republic of Ireland, Prime Minister Bertie Ahern, set forth their new plan -- they called it "The Way Forward" -- in Belfast Friday. Pundits there immediately remarked that this latest proposal to end decades of stalemate was striking in one regard: It prompted a strongly one-sided response.

The plan called for Northern Ireland's new provincial cabinet to take governing power next week with two cabinet members from the leading republican party, Sinn Fein, which supports union with Ireland. Only after that would Sinn Fein's allied street army, the Irish Republican Army, be required to start giving up its arsenal of illegal weapons.

That sequence was just fine with Sinn Fein and other nationalist groups. But the unionists, who support remaining part of Britain, have been demanding disarmament first, followed by governing authority.

Most of the previous proposals that British prime ministers have offered to cure the running sore of sectarian warfare in Northern Ireland have been carefully designed to appeal to all sides in the conflict: the mainly Protestant unionists; the mainly Catholic nationalists, or republicans; and moderate groups that mainly want to end the fighting.

But when Blair unveiled "The Way Forward," his proposal received warm acceptance from republicans and moderates -- and heated denunciation from unionists. As Blair told the Commons today, his job now is to convince the province's largest political party, the Ulster Unionist Party, that this plan is "the best chance for peace we will have this generation."

The strategy for doing that reportedly involves a series of public meetings -- probably at No. 10 Downing Street, London's equivalent of the White House -- with all major parties. In these sessions, Blair presumably will make some alterations in his initial plan.

Unionist politicians will then stand on the front steps of No. 10 and announce that they have forced Blair to accept changes making the proposal more palatable to unionism. Nationalist politicians will stand on the same front steps and groan about the changes, but say that the deal is still barely acceptable to them.

"You need some theater," said Paul Bew, professor of Irish Politics at Belfast's Queen's University. "You need to let everybody participate, publicly."

For many political leaders in Northern Ireland, looking tough is an art form. There was a neat example of this Friday, when the Ulster Unionist leader, David Trimble, received a telephone call from President Clinton -- and reportedly refused to pick up the receiver.

In a similar display of toughness, Trimble has been demanding that Blair fire his minister for Northern Ireland affairs, Marjorie Mowlam. She is the most popular woman in Blair's cabinet. But London newspapers said today that Mowlam will likely be moved next week to a new job, as a sop to Trimble.

[Trimble was quoted Tuesday as saying he had contacted Clinton to seek help on the stalled peace process in the British province. The Times of London reported that Trimble phoned Clinton on Monday because of what an aide called the gravity of the situation in Northern Ireland.

["I contacted Mr. Clinton. I asked him to help me on certain specific matters and I think he will do what he can," the newspaper quoted Trimble as saying.]

When Blair announced his plan last week, he sought to paint the unionists into a political corner: They could either accept a sequence they do not like, he said, or be remembered as the party that killed the peace process.

But Blair also needs something positive to offer the unionists to help them accept his plan. He told Parliament today that Sinn Fein would have to quit the all-party executive immediately if the IRA failed to start disarming on schedule and he would encourage other parties to govern without them. He pledged that unionists would not be "left in an executive with people keeping a private army and intending to use it."

Blair is also said to be working on ways to let the unionists' natural allies, the Protestant members of the Loyal Orange Lodge, carry out some of their controversial parades during this summer's "marching season."

But the prime minister's job was made a little tougher today when Northern Ireland's Parades Commission ruled that a big Orange march set for July 12 cannot pass through a Catholic neighborhood. That will presumably anger the unionists -- just as Blair is working on a strategy to win them over.