I agree with this statement, to a limited degree. Protests are large and frequent in the US by almost every group against or for almost any issue, but with limited effect on actual policy. Where the will of the people is transparent and most effective is in elections, where majority rule actually does count for something.
Another example of the will of the people influencing U.S. foreign policy would be in Somalia. When the media began showing the photographs and video of the U.S. troops being dragged through the streets, the outcry of the American people was loud enough for President Clinton to hear and choose to remove our forces.
Absolutely it can. It does not always have to, but it certainly can.
For example, it was the opposition of many people to the Vietnam War that was one of the major reasons that the US got out of the war. Not everyone disliked the war, but enough people did that Nixon was influenced to try to get out of the war.
I think that we are also influenced by public opinion to support Israel very strongly. It seems to me that we might push them harder to be nicer to the Palestinians, but there is a very strong pro-Israel lobby in the US.
Presidents can resist pressure from the people, as George W. Bush did when the war in Iraq was very unpopular. However, public opinion can definitely have an influence on our policy.
In any democracy the will of the people plays an important in influencing all government policies including the foreign policies. The USA is no exception to the common rule.
To begin with the members of political parties that fight election and form government are composed of representatives of the people. These members of political parties, and the political parties exist to represent the people and they cannot gain enough public support or political power without convincing the people that they are acting in their interest.
At times, the general public is not very active in supporting or opposing the foreign policy issues, as they are unable to relate it directly to their own or country's interest. Therefore, in normal course, the government is able to decide on the matters of foreign policy quite independently of the public opinion. When public opinion does build up on any specific issues, it is not easy for government to ignore it. The answer posted above gives the example of public view on Vietnam war influencing government policy. Another good example is US entry in the World War II. America did not directly enter the war because of the public sentiments against it. However, the Pearl Harbour attack dramatically changed the ground situation as well as public opinion, opening the way for major direct US involvement in the war.