śrī-rājovāca
bhagavān bhīṣmaka-sutāḿ
rukmiṇīḿ rucirānanām
rākṣasena vidhānena
upayema iti śrutam
sri-raja uvaca -- the King (Parikshit Maharaja) said; bhagavan -- the Supreme Lord; bhishmaka-sutam -- the daughter of Bhishmaka; rukminim -- Srimati Rukmini-devi; rucira -- charming; ananam -- whose face; rakshasena -- called Rakshasa; vidhanena -- by the method (namely, by kidnapping); upayeme -- He married; iti -- thus; srutam -- heard.
Srila Sridhara Svami quotes the following smriti statement: rakshaso yuddha-haranat. "A Rakshasa marriage takes place when the bride is stolen from one's rival suitors by force." Similarly, Sukadeva Gosvami himself has already said, rajnah pramathya: Krishna had to beat down opposing kings to take Rukmini.