Jonas shared nationalist sentiments with the b'hoys, but expressed them mostly within established institutions rather than through bare emotions. The New York City militia was as much a political and social arena as it was military. There was pride in behaviour, dress and tradition. These regiments were among the staunchest groups to adhere to the prevailing predjudices against recent immigrants. One of the more prominent regiments was the Tompkins Blues, in which Jonas was an ensign as early as January of 1845.(1) Jonas appears with that rank on a list of an organizing committee for a regiment ball at Niblo's Garden at that time. In May 1847 New York State created the Twelfth Regiment of volunteer militia, a part of what later became the New York State National Guard.(1) Eight companies in the Fourth Brigade, all based in New York City, comprised the new regiment, including Tompkins Blues. The first officer of the 12th, elected 6 August 1847, was Jonas, who accepted the commission of major on 1 September.(1) Capt. Edward Vincent of the Light Guard, another company in the 12th, had commanded the regiment over the summer by default as captain with seniority. Henry G. Stebbins and John Jacob Astor III were elected colonel and lieutenant colonel of the regiment in September, but didn't accept their commissions until 15 May and 26 June 1848 respectively.(1) At that point Stebbins became senior officer of the regiment. To explain the delay in those two commissions, a history of the 12th says that recruitment for the Mexican War was the priority in 1847, more so than the formal organization of the regiment. It isn't explained how this was related to the delay.
     The rank of major in the 12th appears to have been retired when Jonas resigned about September of 1850.(1) In July of 1872 the Old Guard of the Twelfth Regiment was formed as an honorary military unit of veteran and retired soldiers headed by Jonas as major.(1) Published histories of the regiment lack substantive information about the formation of the Old Guard, and one publication doesn't mention that Jonas was ever a member of the regiment.

1.