European Commission President Jose Manuel Barroso warned on June 19 that unless agreement is reached, the EU will lose global credibility and its capacity to act will suffer.
The upcoming summit, which opens on June 21 in Brussels, has been built up by EU leaders as a "do-or-die" event for the bloc.
The EU's outgoing German presidency wants the summit to agree on an outline of a new so-called Reform Treaty to replace the more ambitious draft EU constitution that was rejected by French and Dutch voters in 2005.
The French and Dutch rejections of the constitution pushed the EU into a major political crisis, casting doubt on the bloc's ability to function with 12 new members in the wake of enlargement.
But attempts to reach a new, more limited treaty that would be approved by national parliaments -- and not popular referendums -- are being blocked by Poland. Warsaw says proposed new voting rules under the treaty would give it too little power, while Germany would have too much.
Currently, both stand almost equal, although Germany has twice as many people as Poland.
An overwhelming majority of other member states support the proposed new voting rules.
Loss Of Credibility
European Commission President Jose Manuel Barroso warned on June 19 in Strasbourg that the challenges that the constitution attempted to address "will not go away." He said a new treaty is needed if the EU is to retain its global credibility.
"How can we, Europeans, convince the rest of the world that we are serious when we speak about tackling climate change, tackling the issues of the globalized world -- from international terrorism to aiding developing countries -- when we are not even able to agree on our own institutions?" he asked.
Proponents of the treaty argue the EU needs more majority decisions and an easier way to reach them.
The draft treaty says majority decisions will be adopted if supported by 55 percent of EU countries, representing at least 65 percent of the bloc's population.
Square Roots
This is the so-called double-majority formula. And compared to the situation now, it would greatly boost Germany's power.
Poland, which in recent years has been very critical of Berlin, opposes the double-majority idea. Instead, Warsaw has proposed what it says is a fairer system for smaller and medium-sized countries, where voting strength would be based on the square root of a country's population.
Under the Polish proposal, countries would be compared in terms of the square root of their populations, which would greatly reduce the differences between them.
Warsaw has threatened to veto all new treaty talks without such a change.
Earlier this month, Polish Prime Minister Jaroslaw Kaczynski even said he would "die for the square root." Poland's position has angered some other EU nations. But it had especially upset Germany.
German Chancellor Angela Merkel said on June 19 in Berlin that Poland had "squandered" the chance to lead the EU's new member states.
Historical Animosities
Many German observers have suggested Poland's current leaders are obsessed with taking revenge on Germany for its historical acts of aggression against their country.
Poland leaders have frequently recalled the untold suffering their country suffered at the hands of wartime Germany.
The influential German daily "Frankfurter Allgemeine Zeitung" wrote on June 17 that the Polish prime minister and his twin brother, President Lech Kaczynski, have viewed Germans "since kindergarten as the people of the SS death units."
The paper warned that a split and weakened Europe would be dangerous for Poland itself, pointing to Warsaw's very strained relations with Russia.
European Commission President Barroso on June 19 also issued a veiled warning, saying the absence of a new treaty undermines EU "solidarity." Poland has repeatedly appealed to the EU for solidarity in its spats with Russia.
'Only Losers'
Barroso appealed to all EU leaders to avoid confrontation at the Brussels summit.
"I appeal to all heads of state and government, let us be decisive, let us be constructive," he said. "Let's not be guided by an outdated language of victory [and] defeat."
He said that without success at the summit "there will only be losers in Europe."
While Poland remains the hardest to please, other countries also have their own concerns.
Britain, traditionally skeptical of EU integration, wants to downscale the proposed treaty to avoid a domestic referendum. London's main objections are against strengthening the EU's common foreign-policy and criminal and justice powers.
The Netherlands is also skeptical of a number of the new treaty's central federalist-leaning ideas, as is the Czech Republic.
Whatever the outcome of the summit, intense discussions are certain to continue throughout the EU's next six-month presidency, held by Portugal, to culminate in another heated summit in December.