R.I. Gen. Laws § 17-25-21: Primary elections.

Any candidate eligible to receive public funds and electing to receive these funds who is challenged for nomination for general office in a political party primary shall be permitted to raise and expend an additional amount of funds equal to one-third (⅓) of the maximum allowable expenditure amount for the office or equal to the total amount spent by the candidates’ opponent or opponents in the primary, whichever amount is less. The additional amount received in contributions must be expended prior to the primary election. Any candidate eligible to receive public funds and electing to receive these funds may use public funds made available pursuant to this chapter for any allowable expense, as defined in § 17-25-20, to seek party nomination for general office.