Question

Within months of his inauguration in January 2001, President George W. Bush announced that he wanted to begin building a missile defense shield for the United States because __________.
he did not trust the Russians to honor disarmament agreements
Russia refused to ratify the START II Treaty
he was concerned about certain other nations obtaining nuclear missiles
the ABM Treaty was no longer in effect

Answer 1

Within months of his inauguration in January 2001, President George W. Bush announced that he wanted to begin building a missile defense shield for the United States because he was concerned about certain other nations obtaining nuclear missiles.  

on the other hand, the ABM was no longer in effect due to president's Bush announcement regarding the withdrawal of the United States from the ABM Treaty.