Yes. The Federal Government is constituted by the Powers of the Union, which are the three branches of government: the Legislature, the Executive and the Judiciary. The executive is basically the President of the United Mexican States, who is head of state, head of government and commander-in-chief of the armed forces.
competing political parties
No. It was a federal presidential republic, but president Porfirio Diaz is in fact considered a dictator.
Mexico has had 14 elections since 1920. Many did not consider it, however, to be a democracy until 2000 when a party other than the dominant PRI won it's first election.
Presidential
Democracy
Yes. Although imperfect, Mexico is a democracy.
Mexico is ruled by its people - it is a democracy.
Mexico has been a democracy where the citizens can elect a president and representatives since 2000.
Democracy
It didn't.
The necessity of comprimise
USA, The Philippines, Mexico and others