Using the infinitive with “to” does not indicate purpose, but rather an expected future event, and its expanded form in standard English could be, in the second headline, “The border patrol commander is to leave Minneapolis …” or “The border patrol commander will leave Minneapolis …”.

With regard to discursive effect, the stylistic device typical of journalistic English manifested in the infinitives “to issue” and “to leave” conveys meanings of objectivity, detachment, and factuality.

Considering the discursive genre involved, particularly in newspaper headlines, the infinitive expresses a near future with high probability, and the synonymous forms “will issue” or “is going to leave” are likewise standard and more suitable in headline constructions.

The second headline avoids indicating who made the decision, whether it was a dismissal, a resignation, or a removal, and whether it is temporary or permanent, thus leaving this information for the body of the news story.

The infinitive keeps the headlines shorter, more direct, and more neutral. This serves three genre-related goals: linguistic economy, visual impact, and apparent neutrality.