If you have it lying around, $50,000 is the upper limit on campaign donations to the Manhattan district attorney. Concerned about a conflict because you are an attorney in Manhattan’s criminal courts? No problem!

That’s the head-scratching reality of the campaign finance rules for city DAs, which are getting new and needed attention: Just this month, reports emerged that Manhattan DA Cyrus Vance Jr.’s office decided not to pursue charges in high-profile matters involving Donald Trump Jr. and Ivanka Trump, as well as disgraced movie mogul Harvey Weinstein. In both cases, lawyers associated with the people involved gave to Vance’s campaign after the matters were resolved in the individuals’ favor.

Vance has denied impropriety and wisely returned some donations. This week he said a nonpartisan center at Columbia University will conduct a review “of how we handle campaign contributions.” Regardless, this crucial justice system position must command the public’s trust. That’s why it’s time for strict new reforms about who can donate to campaigns of NYC district attorneys and when.

NYC’s five district attorneys are outliers from the city’s decent campaign finance law. Donations to the mayor’s campaign are capped at $4,950; donors doing business with the city max out at $400. DAs are bound only by shamefully loose state law, with insanely high limits up to $50,000 for some districts, depending on voter registration.

Dreams of real reform — like a publicly funded voucher system providing small sums to donate to campaigns — would likely die in Albany. But city DAs could call for their offices to be within the city campaign finance system. The State Legislature could pass restrictions for all of the state’s 62 district attorneys. Manhattan Assemb. Dan Quart has proposed a database of lawyers who work criminal cases, who could then donate only small sums: a good concept, though perhaps a more effective method exists.

Ultimately, those who can benefit from actions taken by a district attorney, especially defense lawyers for high-profile clients, shouldn’t be donating big bucks near potential cases. Powerful prosecutors must be unswayable, and our campaign finance system must make that clear.