It was perfect timing. Acting U.S. Attorney Joon H. Kim and Manhattan District Attorney Cy Vance had just pulled back the sword on Thursday morning, announcing there would be no criminal charges filed against Mayor Bill de Blasio regarding his fundraising practices.

Minutes later, de Blasio was live on WNYC radio for a pre-scheduled appearance.

He batted away questions about the inquiries, one of which investigated donations to his political nonprofit. Those donations sometimes came from people with business before the city, but the nonprofit wasn’t bound by campaign finance laws.

Another inquiry looked into his effort to help Democrats try to take control of the State Senate in 2014. To do so, his aides urged donations from city businesses and unions to upstate county committees, who gave them to candidates — flouting the intent of campaign finance limits, but not crossing the legal line.

The prosecutors rendered their judgment that de Blasio had committed no crimes, and the mayor said he was looking forward to getting back to work as usual.

Asked for a last response on the situation, de Blasio said only that he wanted “full public financing of elections” from city to federal levels.

“The system is fundamentally broken.”

Campaign finance in NYC is already complicated

The system in NYC is complicated. Candidates for high city office can accept only $4,950 from individual donors, less from those with business before the city. A matching-funds program is designed to favor small donors: participating candidates receive $6 for every $1 in donations up to $175.

That’s not full public financing, typically taken to mean that candidates who raise over a minimum would be given a block sum — no need to run around looking for donations. If self-funding candidates flood the race with more money, the candidates might be able to get more.

That kind of system was attempted in some states — including Arizona and Maine — and then constrained by the Supreme Court after a Citizens United-era challenge.

New York City’s system is a kind of hybrid that has many of the benefits of public financing but lots more paperwork.

Take the case of City Councilwoman Margaret Chin of Manhattan. This week, records showed she’d gotten $275 reimbursed from a total donation of $675 to de Blasio’s 2017 campaign. Why? Her name appears on the city’s strict Doing Business database, even though she says she gave up positions in advocacy lobbying organizations Asian Americans For Equality (AAFE) and the New York Immigrant Coalition (NYIC) in 2008. She is trying to fix the error.

The tight rules also snagged actress Cynthia Nixon, who gave too much to de Blasio (double the $4,950) and was duly reimbursed. The system worked.

Full public funding might be simpler

The real issue with the current system isn’t mistaken donations like Chin’s or Nixon’s, but significant loopholes — like the political nonprofit de Blasio used early in his term. Use of the now-shuttered nonprofit raised questions given the large donations allowed — the $100,000 from a supposedly rat-repellant garbage bag company, for example, which came before a multimillion-dollar deal with the city. The nonprofit’s structure allowed attempts at favor-currying that all kinds of public financing attempt to avoid.

So de Blasio is right that the system in that case broke.

The system also didn’t work in the issue District Attorney Vance was investigating, in which de Blasio’s team helped funnel funds to upstate State Senate candidates in their effort to retake Albany for the Democrats. In a detailed, 10-page letter released Thursday, Vance showed how the effort, at first led by aides to de Blasio and Gov. Andrew M. Cuomo and then largely de Blasio’s, limited the effect of campaign finance. Always operating within the law, the effort meant that in a year when unions would have only been able to give $10,300 to a campaign, the runaround used by the mayor’s team allowed them to donate $102,300.

Vance recommended further guidance from the state Board of Elections on this issue; also, “legislation may be necessary to clarify the Election Law and to prevent any workarounds that might undermine the purpose of the contribution limits.”

Full public financing isn’t anywhere on the table, so less-sweeping fixes like contribution limits are the system we have. De Blasio worked within the system as it was, and as prosecutors said Thursday, he didn’t break the law. But he’s right that the system could use some change.