W] e should not be considered a `second-shot'forum... where secondary, back-up theories may be mounted for the first time

Particularly on an appeal from the grant of summary judgment, we are reluctant to entertain new arguments because they have not been considered by the trial court.

But Cohen-Esrey did not make this argument in district court, and the argument is therefore forfeited on appeal.

—generally, appellate court will not consider issue raised for first time on appeal; vague, arguable references to a point in the district court proceedings do not preserve the issue for appeal

—issue must be `presented to, considered [and] decided by the trial court'before it can be raised on appeal

Propounding new arguments on appeal in an attempt to prompt us to reverse the trial court undermines important judicial values. In order to preserve the integrity of the appellate structure, we should not be considered a `second-shot'forum, a forum where secondary, back-up theories may be mounted for the first time

As a general rule, this court will not consider an issue on appeal that was not presented to the district court.

—noting that we generally do not resolve issues on appeal unless they are presented, considered, and decided by the district court

To the extent this is intended to be a different characteristic than having refused to join a gang, we do not consider it, because it was not properly raised before the Immigration Judge or the Board of Immigration Appeals.