Rep. Edward J. Markey is calling on all candidates who might run in the special election to succeed Sen. John Kerry to urge super PACs and other third-party groups against spending money in the race.

The thing is, Markey was the only declared candidate as of press time.

“People’s pledge” is the term Democratic Sen. Elizabeth Warren and former Republican Sen. Scott P. Brown used to describe their agreement to eliminate outside spending in their blockbuster 2012 campaign.

Over the weekend, Brown, who has not said if he is running, earned attention for engaging with a so-called “Internet troll.” He responded to a taunt in his Twitter feed with three tweets — two of which had typographical errors. He ultimately deleted them, but not before reporters and Democrats took notice.

Among them, according to reports, “Bqhatevwr,” which appeared to be a mis-typed “whatever.”

Kerry’s nomination to be secretary of State is expected to breeze through Senate confirmation this week. Gov. Deval Patrick is expected to announce his temporary appointment to replace Kerry soon thereafter. The primary is set for April 30, with the special election slated to be held on June 25, according to a Monday report in The Boston Globe.