(CNSNews.com) - The outcome of Sunday's closely fought parliamentary election in Poland could affect how the country relates to both the United States and European Union.

The former Soviet satellite has been a strong ally of the U.S. in Iraq and also is the Pentagon's preferred location for a battery of interceptor missiles to help protect America and its allies against any future missile attack from countries like Iran.

Under its current conservative-populist government, Poland also has been at odds with its European Union partners over questions of sovereignty and differences over abortion, homosexual rights and the death penalty.

Prime Minister Jaroslaw Kaczynski called elections two years early after his government collapsed amid coalition infighting earlier this year. The prime minister's twin brother, Lech, is Poland's president.

Opinion polls place the Kaczynskis' Law and Justice Party a few points behind the Civic Platform, a conglomeration of leftists, libertarians and conservatives, although it looks like neither will be able to govern without a coalition partner.

Both main parties have their origins in different wings of the anti-communist Solidarity trade union movement. The third-placed party in the polls, known as the Left and Democrats, has its roots in the former communist party and is a potential coalition partner should Civic Platform form the next government.

Poland has some 900 troops in southern Iraq, supporting and training Iraqi soldiers and police. Kaczynski has vowed to keep them there despite recent setbacks.

In an apparent bid to force Poland to withdraw, Shi'ite insurgents have stepped up attacks against the troops, and Poland's ambassador in Baghdad was wounded in a deadly bomb blast targeting his convoy earlier this month.

Although Civic Platform supported the Iraq war in 2003, it says it will withdraw the troops by the middle of next year if it wins the election. Civic Platform leader Donald Tusk during a televised debate last week suggested that Poland gets little in return from the U.S. for its contributions.

Defense Minister Aleksander Szczyglo said Monday that by making the military mission an election campaign issue, opposition parties were increasing the risks facing the soldiers.

Another key issue facing the next government is the siting of 10 interceptor missiles on Polish soil as part of the Pentagon's proposed ballistic missile defense (BMD) umbrella.

The plan to place the silo-based missiles in Poland, and an associated radar facility in the Czech Republic, is a major source of contention in both countries.

Both governments support the proposal, but public opinion is split. Among other things, many worry about the possible consequences of Russia's strong objections.

President Vladimir Putin said on Russian television Thursday that retaliatory steps would be taken if the BMD project goes ahead, although he did not elaborate.

Relations between Russia and Poland have been sour since the Kaczynski government took office in 2006 and are likely to worsen further should the BMD shield go ahead.

Civic Platform has not ruled out cooperating on BMD, although one of its most prominent members, Radek Sikorski, has been pressing for more generous aid package for Poland in return, including upgraded Patriot missiles to protect Warsaw against medium-range missile attack. Sikorski, a former defense minister in a Law and Justice government who moved to Civic Platform, is considered a key figure to watch in Poland and a possible future president.

A change of government in Warsaw could bring smoother relations with the E.U., which Poland joined in 2004 after a lengthy accession process. Its dealings with the E.U. have been marked at times by distrust and disagreements over what many Poles see as attempts to force liberal "European values" on the predominantly Roman Catholic country.

Poland is one of only three E.U. countries to restrict abortion; it has clashed with European institutions over homosexual rights; and its objections threw into disarray E.U. plans to hold a day against the death penalty earlier this month.

Poland has also differed with the E.U. over institutional issues, accusing the bloc of treating the former communist newcomers as second-class members.

Polish objections have been among those complicating lengthy efforts by the E.U. to endorse a new reform treaty and end an institutional crisis triggered by referendums in 2005 rejecting a new E.U. constitution. On Friday, the new treaty appeared to be a done deal after talks in Lisbon.

"Poland should ... be wary of Brussels' gravita/-tional pull, because closer ties with the E.U. will come at the expense of its relationship with the United States," Heritage Foundation scholar Sally McNamara argued in a memo.

"A significant loss of sovereignty is not something that makes for a strong coalition ally," she said. "Instead, Poland must pursue a relationship with the E.U. that is based on free trade and voluntary intergovernmental cooperation."

Turnout in Polish elections has traditionally been low -- 40 percent in the last parliamentary election -- and the country's Catholic Church this week urged voters to participate.

A letter read out to congregations said voters should support those whose views are not contrary to the Catholic faith, although it also said the church "does not identify itself with any political party."

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