Gaius Caesar does not really understand what you mean by "platform." One of my legates informs me that in this time it is customary for magistrates to openly state intended legislative programs and policies during their canvass for election. This is a concept that is entirely alien to me, and did not exist in elections within the city.^1

If you are asking why the civil war began, it was due to the inflexibility and treachery of Cato and his supporters. I, Gaius Caesar, would be remiss if I were to accept their insults and allow them to stain my dignitas, and with it the welfare of the state, without just punishment. They rejected the comitia's resolution to allow me to run for the consulship in absentia, they ignored my proposal to lay down my arms alongside Pompey (despite an overwhelming senatorial vote for it--only 22 senators voted against the motion), they beat the sacrosanct tribunes and expelled them from the city. What sort of a man would I, Gaius Caesar, have been to ignore this great treason and stain on the city and people? What sort of condemnation would I have brought down upon my own head, what sort of infamy would be attached to my wounded dignitas?

If you ask why Cato was so determined to insult me unjustly, I suppose it must come down to my consulship of 59. In that year Gaius Caesar held the consulship alongside Marcus Bibulus, who ineffectually attempted to curb the ambitions of myself and my great allies, Gnaeus Pompey and Marcus Crassus. Cato was among those who disrespected my consular authority and the power and right of Pompey and Crassus, who had held the consulship in 70. Gaius Caesar's legislation was passed justly and by the vote of the people, yet Marcus Cato, in his hatred for Pompey and even for Gaius Caesar myself, hoped to stall proceedings by speaking until nightfall, in direct defiance of the will of the comitia--I am told that this is called "filibustering" in your language. Thus, I had him escorted to prison, though in my wisdom I did not order him placed in chains but allowed him to go free, having been led off the speaker's platform. Likewise Marcus Bibulus attempted to prevent the legitimate assembly of the voting comitia by invoking the archaic institution of the consular inspection of omens from the safety of his own home, to which he had retired, knowing full well that he had no right to stop the lawful assembly of the comitia and the will of his consular colleague. In their futile attempts to unjustly wrong the people of the city from exercising their will at the ballot and their failure to humiliate a consul and two consulars they cast their invidia on me, Gaius Caesar.^2

If you ask why I, Gaius Caesar, incurred the enmity and invidia of those who eventually murdered me in the Theater of Pompey, I must say that I do not fully understand their motives. Some were old enemies of mine, whom I had spared in the civil war, for the good of the state, but others were my great friends. I must only imagine that for some the pain of seeing Gaius Caesar pre-eminent in his dignitas proved to be too severe a wound, and that for others the naturally subversive character of the low-minded took hold of them. I lament that Marcus Brutus, whom I treated as though he were my own son, and that Decimus Brutus, whom I wrote as my secondary heir in my will, were so misled by Cassius. Some I expect may have misunderstood the affair of the Lupercalia, believing Gaius Caesar to be aiming at the kingship--an absurd idea, as the greatness of a man lies in his dignitas alone, not in bizarre and tyrannical titles.^3

1. As Shackleton Bailey said, no Roman politician ran on a platform, and the concept would have been entirely foreign. Magistrates held office for a single year, and though they might have an intended legislative program that they immediately pushed through (e.g. the leges Clodiae, which were passed the very day that Clodius assumed the tribunate) these need not have been declared openly and usually weren't. The idea of a "binding" political platform stated in advance wouldn't have made sense for the Roman statesman, who competed in the political arena to increase his own dignitas and who was quite comfortable with forging and re-forging political alliances. There was nothing remotely approaching a party system, and politicians changed tactics and legislative agendas all the time--a man who was a staunch devotee of popularis tactics during his tribunate might, more often than not, find himself solidly backing Cato during his praetorship.

2. For a perhaps more...balanced view of Caesar's consulship, I highly recommend you consult Gelzer's biography of Caesar, which also does a good job of explaining the realities of Roman political life. That Cato's hatred of Caesar was more than a little self-destructive and obsessive, however, is well-known (see Cicero, ad Atticum 2.1, in which he famously expresses his belief that Cato, though well-intentioned, does harm to the state by obsessively attempting to prosecute Caesar, his white whale)

3. The Lupercalia affair is generally thought in our sources to be the final straw for the conspirators, who had been plotting for at least a year by then. What exactly Caesar's intentions were (or whether he even planned it out) are pretty unclear and very debated. Even our texts don't seem to adequately understand what was going on. This thread discusses some of the possibilities, but it's a pretty murky affair