Private briefing took place Friday, included unidentified LGBT leaders
Vote expected later this month on issue
Deadline for DOJ to take action is Feb. 28
Justices poised to issue most significant rulings on gay rights
Carney defers questions to Justice Department
Letter asks DHS to place on hold marriage-based green card applications
Carney says administration will leave issue to Congress
Griffin among 13 leaders to participate in discussion
Carney says religious institutions can decide their own sacraments
Carney won't say if Obama wants nat'l ruling in favor of marriage equality
