ubhayartho mato mama
Only one who has conquered all opponents in every direction can perform the Rajasuya sacrifice, O almighty one. Thus, in my opinion, conquering Jarasandha will serve both purposes.
Sri Uddhava here explains that only one who has conquered all directions is entitled to perform the Rajasuya sacrifice. Therefore Lord Krsna should immediately accept the invitation to participate in the sacrifice, but then He should arrange to kill Jarasandha as a necessary prerequisite. In this way the kings’ request for protection would be fulfilled automatically. If the Lord would thus adhere to a single policy — namely, seeing that the Rajasuya sacrifice was performed properly — all purposes would be fulfilled.
According to Srila Rupa Gosvami in his Bhakti-rasamrta-sindhu, one of Lord Krsna’s qualities is catura, “clever,” which means that He can perform various types of work at the same time. Thus the Lord could certainly have solved the dilemma of how to simultaneously satisfy King Yudhisthira’s desire to perform the Rajasuya sacrifice and the imprisoned kings’ desire for freedom. But Krsna wanted to give His dear devotee Uddhava the credit for the solution, and thus He pretended to be perplexed.