LONDON — David Cameron is feeling the weight of the incurable feud over Europe within his own party, a load that is overshadowing the British prime minister's trip to Brussels for a summit to save the euro.
Britain has its own currency - but the crisis over the euro, used by 17 other EU nations, has inflamed his Conservative Party's long-running division over Europe, a schism that brought down former Prime Minister Margaret Thatcher and bedeviled her successor, John Major.
Some Conservatives back Mr. Cameron's stance that Britain's priority is to solve a European debt crisis that has reverberated at home and around the world.
But other Conservatives are pressing Mr. Cameron to seize the moment and wrest new concessions from the 27-nation European Union.
France and Germany are pressing to rewrite EU treaties so that at least the eurozone has closer fiscal policies - and maybe even the entire EU.
Their urgent need for these quick changes to make sure the eurozone doesn't disintegrate leaves them vulnerable to any British demands.
Britain, for its part, is wary of transferring any more powers to the central EU headquarters in Brussels, or seeing its own power reduced as 17 other EU nations grow closer.
Many Conservatives are calling for a referendum on any new deal with the EU. Lawmaker Bernard Jenkin on Thursday urged the prime minister to grab a "win-win-win" opportunity to call a nationwide vote.
"He'd have the Conservatives behind him, the British people want a referendum, the British people want a different relationship with Europe, and he would have a much stronger hand to negotiate," Mr. Jenkin said.
Many in the party, and the country as a whole, want to simply get out of the European Union.
But Mr. Cameron's less combative approach drew support Thursday from the previous Conservative Party leader, Michael Howard.
"I would like to see a rebalancing of powers between Britain and Brussels, and I hope that at some point we can return to that agenda," Mr. Howard told BBC radio.
"What is pressing at the moment is the need to help the eurozone overcome its crisis, because the world economy is in a very fragile state and a disorderly break up of the eurozone could bring about an economic catastrophe on a global scale," Mr. Howard added.
Mr. Cameron told the House of Commons on Wednesday that a referendum would be needed only if a new European Union treaty took more powers away from London, but that would probably not be the case if the outcome is a deal among only the 17 nations that use the euro.
Conservative lawmaker David Davis disagreed. A eurozone deal, he argued, would require an entirely new structure for the EU. Any 17-nation fiscal union that imposed tighter discipline on member countries would have "huge implications for Britain, whether or not we are actually directly involved."
That point also was made by London Mayor Boris Johnson, a potential rival as Conservative Party leader, and Owen Patterson, a member of Mr. Cameron's Cabinet.
It is a ticklish position for the prime minister, who heads a coalition government that includes the Liberal Democrats, whose leaders generally favor closer ties to Europe.