As expected, the Delaware attorney general’s office moved Tuesday night to intervene in Bank of America’s proposed $8.5 billion settlement with Countrywide mortgage-backed noteholders. The Delaware petition to intervene and supporting brief are notable for their moderate tone, in contrast to last week’s fiery objection and counterclaims by the New York attorney general. Tuesday’s filings, signed by Delaware deputy AG Jeremy Eicher, said that Delaware is concerned about BofA’s indemnification of the MBS trustee, Bank of New York Mellon — the same conflict-of-interest allegation raised by just about every intervenor who so far has surfaced in the case. Delaware, which noted that two of the Countrywide MBS trusts are Delaware vehicles, argued that it needs more information about the proposed settlement in order to protect investors.

The real story, though, is that both the New York and Delaware AGs believe BofA and BNY Mellon can’t resolve their liability to MBS investors without including regulators in the deal. After all, the proposed $8.5 billion settlement encroaches on turf already claimed by New York AG Eric Schneiderman and Delaware AG Joseph Biden III; in June, the New York Times broke the news that the New York and Delaware AG offices were investigating the banks involved in the mortgage-backed securitization process — including sponsors and underwriters such as Countrywide and BofA and trustees such as BNY Mellon.

The Delaware and New York securitization probes, which are running parallel to the 50-state AG investigation of banks’ mortgage foreclosure practices, gave Schneiderman and Biden a platform to argue that MBS investors, as well as homeowners, are affected by slipshod mortgage underwriting practices and widespread foreclosures. In the wider foreclosure-resolution negotiations between mortgage lenders and state AGs, New York and Delaware have taken a lead in calling for banks to also address MBS liability.

“We have a close working relationship with New York,” Delaware deputy AG Ian McConnel told me Wednesday. McConnel said the states have been investigating the entire securitization process, from the documentation of mortgage loans backing securities offerings to communications with investors after underlying loans began to go into default. (The New York AG’s counterclaims in the BofA settlement, for instance, asserted that BNY Mellon breached its duties as trustee in the Countrywide MBS offerings because the bank didn’t demand documentation from Countrywide when the notes were offered, and didn’t notify investors when underlying mortgages defaulted.)

The proposed BofA deal would wipe out Bank of America and Bank of New York Mellon’s liability to investors for much of the same alleged wrongdoing that the New York and Delaware AGs are investigating. It would also enact changes in how BofA services mortgage loans, which is what the larger AG group is negotiating with mortgage lenders. The settlement between BofA, BNY Mellon, and Countrywide investors, in other words, attempts to do privately what 50 attorneys general are trying to accomplish in the regulatory arena.