Of course. But Caesar was unlikely to get a fair trial.
Please note, I'm not defending Caesar especially but his conduct whilst consul would give better grounds for prosecution than his actions as proconsul.
OK--you play Cato for a while: how did Caesar's conduct as consul provide a good target for a successful prosecution?
Furius play Cato? To do that he would need to be a miserly, twisted psychophant..However I will try to add some objective observations.
Lets take a look at the situation.
1) Thousands (perhaps 100K +)of demobed veterans and their dependants awaiting their rightfully earned allotments, (think of GI's returning from Iraq and having their DD214 and GI Bill rights witheld).
2) Confirmation of eastern treaties (stabilization of borders and buffer state alliances).
3) A bloc of 20 senators led by Cato who were set to filibuster the consular year into oblivion. A middle of the road senatorial bloc (majority)led by Cicero who advocated compromise as long as senatorial authority was maintained.
4) At this point the "Triumvirate" had yet to be "formed".
5) The Senate was a delibrative body not a legislative body.
6) The Comitia were the legislative bodies and through the Lex Hortensia the Plebiscitia were binding on ALL citizens. Addressing and proposing legislation directly to the Comitia by Consuls was not without precedent. Scipio A had gone this route when he was being shafted by none other than Cato the Elder.
So, Caesar proposes a reasonably drafted (and this can be backed up with numerous secondary sources, Meier, Gelzer, Holland) bill to settle the veteran issue. He is filibustered by Cato, he has Cato dragged off to prison by his lictors (his legal right as Consul to do so), but beats a tactical political retreat through acquiescence after the Cato cronies walkout in protest. Realizing nothing will be achieved going the normal route, he approaches the people via the Comitia Centuriata. He presents his bill, to which his co-consul Bibulus (a Cato crony) publicly decries with the famous statement "You shall not get it EVEN if you ALL want it!". Bibulus subsequently retreats to his house to "Watch the skies" in an effort to forsee "unlucky" days so any legislation passed on that day could be declared defunct. Caesar moving forward passes all his bills through the Comitia.
Find me the "illegality" in the above if you please.
Edit: Point 4, the "Triumvirate" was formed after Caesar initially presented the bill to the senate but before he addressed Centuries