The U.S. missile defense system will also be integrated with the NATO command and control network and missile defense systems of other NATO members.

Gains of Poland

Before the agreement was signed, more than 100 American soldiers and the first batch of Patriot missiles had already moved into a military base in the town of Morag, in northern Poland. This marks the first time American troops have been stationed in Poland since the end of the Cold War.

Poland could achieve three strategic objectives through the signing of the new missile defense pact and the deployment of Patriot missiles.

First, Poland has obtained a symbolic weapon to protect itself. Since the dissolution of the Soviet Union and the Warsaw Pact alliance, Poland has been worried about its homeland security. Obtaining Patriot missiles and forming a military alliance with the United States helps not only alleviate Poland's security concerns, but also enhances its level of military modernization.

The move can also help Poland gain more attention in NATO and the EU. Due to its weak economic and military strength, Poland's actual influence in the two organizations is far below its expectations. By forming an alliance with the United States, especially a military one, Poland's status in the two organizations will naturally rise.

In addition, the U.S. military presence reflects the United States' commitment to Poland. In the early days of his presidency, Obama was aloof from East European allies. Most notably, he gave up Bush's missile defense plan, which disappointed Poland, the Czech Republic and others. This time around, the U.S. troops stationed in Poland, coupled with the new missile defense pact, will serve as an indication of the military alliance that the two countries have forged.

Gains of U.S.

The signing of the new pact is significant for the United States, too. With this step, the U.S. global missile defense system becomes more complete.

Before this, the United States had not only established missile defense bases in Alaska and other places within its borders, but also tried to develop a global missile defense system through military cooperation with Japan and South Korea. The successful deployment of a missile defense system in Poland has expanded this system. Geologically, Eastern Europe is undoubtedly an ideal region.

In addition, the deployment of a missile defense system in Eastern Europe also bears geopolitical significance for the Untied States. With the missile defense system in Eastern Europe as an important part of its global missile defense system and with Poland and the Czech Republic as a base for its future eastward expansion, the United States aims to eventually realize strategic containment against Russia.

In order to gain Russia's support on major international and regional issues, Obama has carried out a series of measures to improve U.S.-Russia relations since taking office. Despite these measures, long-term distrust between the two countries could not be changed in the foreseeable future.

The first Patriot missiles of the United States were deployed in Morag, only 60 km from the Russian enclave of Kaliningrad. To dispel Russian concerns, Poland said it would allow Russia to check the target of the missile defense system in Poland. Hillary Clinton also stressed the defensive nature of the system, and said it would not pose a threat to Russia.

But as one of the key issues affecting U.S.-Russia relations since the Cold War, the deployment of a U.S. missile defense system in Eastern Europe impacted U.S.-Russia relations greatly. This is undoubted.

Russian President Dmitry Medvedev said the United States made the move obviously with Russia in mind. The interceptors deployed in Poland were intended to deal with Russian missiles, he said.

It is possible that Russia will once again adopt tough measures, such as deploying Iskander missiles in Kaliningrad, if its security interests cannot be guaranteed.

In addition, the deployment of a missile defense system in Poland has not only consolidated the United States' leading position in NATO, but also strengthened NATO's military and political role.

The Ballistic Missile Defense Review Report the Pentagon submitted to Congress in February emphasized that the United States will proactively promote the establishment of an integrated missile defense system within the NATO framework and will strengthen cooperation with specific partners.

If NATO's theater missile defense system is completed and integrated into the U.S. missile defense system, it will be able to cover all its European allies. This means there is no longer a need for NATO to develop its own missile defense system.

Actually, the real purpose of the United States is to restrict NATO from developing missile defense capabilities independent of the United States. With this move, the United States strengthens its allies' security reliance on it and is virtually guaranteed to retain a leading strategic position in NATO.

The author is a researcher with the Institute of American Studies of the China Institutes of Contemporary International Relations