The U.S. containment policy faced significant challenges during 1949-1950, particularly with the rise of communism in China and the outbreak of the Korean War. These events demonstrated that the containment strategy was struggling to effectively prevent the spread of communism. Therefore, the statement that the containment policy was not effective is considered true.
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In the period of 1949-1950, the United States' containment policy faced significant challenges, notably with the rise of communism in China and the onset of the Korean War. These events indicated that the policy was struggling to prevent the spread of communism effectively. Therefore, it can be stated that the containment policy was not working effectively at this time. ;