If you analyze the actions of Krishna and don't accept the explanations for them, he's kind of Machiavellian.
1)He goes with Balaram to Draupadi's Swayamvar, supposedly because he suspects Pandavas will be there and they didn't die in jatugriha. Why did the Pandavas go to such a high profile place when they are supposedly hiding from Duryodhana's assassination attempts? Duryodhana himself was there FFS, it would be beyond retarded to go there unless they expressly intended to get an alliance with Raja Drupad, keeping in mind Krishna's own links with Drupad and Draupadi the design of the Swayamvar too reeks of being aimed specifically at Arjuna(Who, again, Drupad too must think to be dead, if we are to believe the stated facts). Drupad's own defeat at Arjuna's hand would have both cemented his belief in Arjuna's ability and made him hate the Kuru polity, so Krishna knowingly fomented an alliance he knew would prove crucial in a potential civil war.
2)Krishna is the nephew of Kunti, who 'mistakenly' gets Draupadi to marry all 5 brothers instead of Arjuna alone. Before Ashwathama killed him, Yudhisthira's son by Draupadi, the grandson of Raja Drupad was heir apparent. Was this the price of his support to the Pandava cause? Also, Arjuna himself was a warrior and always ran the risk of a battlefield death, a marriage with all 5 brothers however served as security against his death.
3)Krishna gives his Akshahini Sena to Duryodhana but joins Arjuna himself on the condition that he won't fight, ensuring the victor would be grateful to him in case either won.
4)Pancala itself couldn't have looked kindly on the rise of Jarasandha and Magadha, Krishna of course got BTFOd by them and had a grudge, all cope about muh 18 gorillion victories aside. By cooperating with Krishna, Drupada would manage to simultaneously weaken both his powerful neighbours, ensuring an alliance with the northern one would just be the icing on top.
Is it just me or would a Machiavellian Krishna make for a much more logically coherent and interesting story? He had no obligation towards Duryodhana, him giving Duryodhana his soldiers and not fighting himself always seemed a bit odd to me in light of that. After all, he is supposed to be a protector of dharma too and he repeatedly extols why Arjuna should commit fratricide to uphold it, so why wouldn't he take sides if he truly believed in what he said?