From his office overlooking the gold-gilded Iowa State Capitol, Tom Miller is confronting the reality of how hard it is to get all 50 state attorneys general to agree on anything. The 66-year-old Mr. Miller, up for re-election Tuesday to his eighth four-year term as Iowa’s top law-enforcement official, leads the nationwide investigation into the foreclosure mess that erupted in September. The attorneys general are scrutinizing whether home-loan servicers violated state laws against deceptive practices by submitting affidavits and foreclosure documents without confirming the paperwork’s accuracy. The investigation could lead to civil charges and inescapable pressure on financial institutions to rewrite a mountain of mortgages. Already, there are signs that state officials are working together closely to gain more leverage over companies such as Bank of America Corp., Wells Fargo & Co. and J.P. Morgan Chase & Co.