Need suggestion

India has a parliamentary government whereas the US doesn't....

That's not really an answer for the question.

The question is about politics, not about forms of government.

For example, the US often indulges in the humanitarian intervention (right to intervene) on other nations, while India doesn't..

One significant difference between American political parties and the political parties of nations using the Westminster system (i.e., a system modeled on the government in London) is party leadership. There is no fortmal leader of an American political party. During a campaign year for the office of President, whoever wins the party nomination becomes the leader. When the election is over, whoever has won the election becomes the de facto party leader, although his or her authority is only moral. No President can kick anyone out of their party, nor punish them for not supporting the party's agenda. Whichever party loses the election essentially has no party leader until the next presidential campaign year.

Also, Presidents are indirectly elected by the entire nation, through the Electoral College, and are not a part of the legislative branch.

In the Westminster system, each party has a party convention in which a party leader is elected. He or she then becomes the spokesman for the party's agenda. Party members who stray from the agenda, or who fail to support the party's agenda in Parliament can be formally expelled from the party. This cannot happen in the United States, although someoone who opposes their party's agenda might well "cross the aisle," which menas that they will become an independent, or join the opposing political party. This happened a few years ago in the United States Senate.

Also, the Prime Minister in a Westminster style system is not elected nationally. He or she is chosen by registered members of the party at a convention. Then, if that party wins more seats than any other party, he or she forms the government and becomes the Prime Minister. However, the party leader only has to be elected in the electoral district for which they stand. In some cases, the party leader stands for election in a "safe" district, meaning a district which will reliably vote for that party. If they fail to win the election in that district, then another member of the party might stand down--resign--and the party leader would then stand for election in the by-election for that seat. Significantly, Prime Ministers are not only the chief executive, they are membes of the legislative branch.

An interesting example of how this all works happened in the most recent election for the Ontario provincial parliament. The Ontario Premier is Dalton McGuinty, the leader of the Liberal Party. In the last election, the leader of the conservative party was John Tory (ironic, no?). As a result of having said something incredibly stupid, John Tory was dogged by the press and the people throughout the campaign, and McGuinty's Liberals won the election. (They were one vote short of a majority, though, which means they have to suck up to the New Democratic Party in order to pass their legislation--it's not a very happy situation for McGuinty.) Worse than that, John Tory lost the election in his riding. (An electoral district in Canada is called a riding, recalling the days more than one hundred years ago when a candidate would get on a horse and ride around the district campaigning for election). Losing the election is often enough for another member of the party to challenge the party leader at the next convention. But losing his seat in the provincial parliament meant that Tory was automatically out. He now hosts a talk radio program in Toronto. One final irony--for a long time, the conservatives in Canada called their party the Progressive Conservative party. The current government has changed that name, but in Ontario, they are still known as Progressive Conservatives. They are the "PC" party.

The issue of leadership, and how the chief executive is chosen is the most important difference between politics in the United States and politics in any nation--like India--which uses the Westminster parlieamentary system.