In Republican Rome political 'parties' would woo victorious generals such as Gaius Marius, trying to win them over to their side.
Of course I am over-simplifying things a little, since political groupings during the Republic were more fluid - being loose groupings based on common interests, which changed over time and depending on the issue, rather than the set-in-stone political parties of today. The concept of 'political parties' of populares vs. optimates (or boni) was largely codified by Theodor Mommsen in the mid 19th, and reflects the politics of his day more than those of Rome - this was also the time that political parties developed in the US.
In the Republic elections for the head of state were simple - the two with the highest number of votes both got the job and were the Consuls for the year. This meant that no one man could hold too much power and aspire having himself crowned as another King. It also made for better government through having two - often adversarial - people in charge, who had to find some sort of common ground.
Before they could stand for election as consul, Senators were legally required to follow the cursus honorum, which started with ten "years" [campaigns] in the military. Cicero is often cited as an exception to this, and Sulla also seems to have skipped the ten season (which may explain why he was such a bad leader!). This martial experience was considered 'good' training for political life, but was also a necessity since Consuls were commanders-in-chief, given imperium to lead Rome's armies. Commands could be prorogued (proconsular imperium), and given to lesser magistrates such as praetors (propraetorian imperium), but all were given to men who had two things in common; they were Senators, and had extensive military training.
The Founding Fathers did not want another monarchy for the United States, so deliberately chose a system of government for and by the people. They rejected Athenian Democracy in favor of the Roman Republican system - which is why we have some slightly archaic concepts such as the Electoral College. Two Consuls with equal power clearly did not work for the Founding Fathers, so they adapted the system slightly for presidential elections - the winner became President, the runner-up became Vice-President rather than Co-President (Article 2 of the Constitution). There were problems in the third and fourth presidential elections, so the method of selecting the VP was changed by the 12th Amendment to the electoral system we have today.
With all the speculation going on about VP choices, I have been wondering whether the Founding Fathers might not have had the right idea. We could just have the two Senators on the ballot, with no VP candidates - the winner becomes President, the runner up VP. Both are uniters who seem able to cross party lines, and the country is in dire need of some unity. Maybe the Founding Fathers' plan would be the way to do it. It would also be the (Roman) Republican way, and in many ways Senators Obama and McCain are like Roman politicians - able to work with and to draw support from the 'other' side - with a country that needs to move beyond the pure partisanship that has proven so divisive.
The whole political leader-come-general general link was of course key in the Roman Republic. I've been blogging a bit lately about Gaius Marius as military leader - but he was probably even more impressive as a politician. Although in most studies he is considered a populares - for taking care of his troops, feeding the poor, enfranchising the Italians - his politics are never that clear-cut and can best be described as situation ethics (or opportunist, depending upon how you see Marius).
Generals today are expected to keep out of politics, as Admiral William "Fox" Fallon discovered when he gave an interview to Esquire in March. But General Jim Jones is clearly a political favorite as well as a highly respected military leader: speculation that he could be VP to Obama ... was briefly crushed by the news that he was already advising McCain. This marine clearly has many friends in politics, and understands Amicitia as well as any Republican Roman in whose footsteps he follows.