For the months leading up to January 49 BCE, both Caesar and the anti-Caesarians composed of Pompey, Cato, and others seemed to believe that the other would back down or, failing that, offer acceptable terms. Trust had eroded between the two over the last few years and repeated cycles of brinksmanship harmed chances for compromise.

On 1 January 49 BCE, Caesar stated that he would be willing to resign if other commanders would also do so but, in Gruen's words, "would not endure any disparity in their sar and Pompey's] forces", appearing to threaten war if his terms were not met. Caesar's representatives in the city met with senatorial leaders with a more conciliatory message, with Caesar willing to give up Transalpine Gaul if he would be permitted to keep two legions and the right to stand for consul without giving up his imperium (and, thus, right to triumph), but these terms were rejected by Cato, who declared he would not agree to anything unless it was presented publicly before the Senate.

The Senate was persuaded on the eve of war (7 January 49 BCE) – while Pompey and Caesar continued to muster troops – to demand Caesar give up his post or be judged an enemy of the state. A few days later, the Senate then also stripped Caesar of his permission to stand for election in absentia and appointed a successor to Caesar's proconsulship in Gaul; while pro-Caesarian tribunes vetoed these proposals, the Senate ignored it and moved the senatus consultum ultimum, empowering the magistrates to take whatever actions were necessary to ensure the safety of the state. In response, a number of those pro-Caesarian tribunes, dramatising their plight, fled the city for Caesar's camp.