3. Service under Federal Rule 4(k)(2) generally is said to call for a two-step inquiry. At step one, the inquiry is whether defendant is subject to personal jurisdiction in any one of the fifty states; at step two, the inquiry is whether defendant’s contacts with the nation satisfy due process. As to the first step, the Seventh Circuit, in an influential decision, held that service may be effected if defendant acknowledges that he cannot be sued in the forum state but declines to identify a state in which jurisdiction is present. See198ISI Intern. Inc. v.

Borden Ladner Gervais LLP, 256 F.3d 548, 552 (7th Cir. 2001). As to the constitutional inquiry, the rule permits the aggregation of defendant’s nationwide contacts. The question is whether “there are sufficient minimum contacts with the nation as a whole.” Abelesz v. OTP Bank, 692 F.3d 638, 660 (7th Cir. 2012).