Underlining the growing tension between Russia and the West, President Vladimir Putin on Saturday signed a decree suspending Moscow's participation in the Conventional Forces in Europe (CFE) treaty.
But Washington is determined to go ahead with building the missile shield in Poland and the Czech Republic despite Putin's objections and proposal to use a radar in Azerbaijan instead.
The talks with Kaczynski, one of Moscow's most outspoken critics and a key U.S. ally in Europe, should bring the plan closer to life.
"We won't be announcing a final agreement in Washington because President Kaczynski will want to do this at home. But we should be much closer to a deal after the meeting," said a senior Polish official who declined to be named.
Washington wants to place interceptor missiles in Poland and a radar facility in the Czech Republic to protect the United States and its allies from missile attacks from what it calls "rogue states" such as Iran and North Korea.
President Bush last month visited both Poland and the Czech Republic, which has already agreed to host the radar site on its territory.
So far Poland has held out, hoping to negotiate related military contracts or other concessions. Other unresolved issues include related legal matters, such as the status of U.S. soldiers on Polish soil.
Polish and U.S. negotiators held a round of talks in late June in Washington and will hold further talks later this month or in early August. Deputy Foreign Minister Witold Waszczykowski, who represents Poland in the talks, expects a deal in September or October.
Polish officials said Bush and Kaczynski will also discuss Poland's participation in the military missions in Iraq and Afghanistan.
Earlier this month, Defense Minister Aleksander Szczyglo said he would not rule out keeping Poland's 900 soldiers in Iraq beyond the end of this year. Poland also has 1,200 troops deployed in Afghanistan as part of a NATO mission.
The government of Prime Minister Jaroslaw Kaczynski, the twin brother of President Lech Kaczynski, has come under fire, even by some of his junior coalition partners, over the unpopular troop deployments.
President Kaczynski will also fly to California, where he will present Poland's highest distinction -- the Order of the White Eagle -- to Nancy Reagan, widow of former President Ronald Reagan, in recognition of his role in the downfall of communism in Europe.
SOURCE: By Chris Borowski