Often, foreigners want to visit the U.S. while a fiancee or marriage case is pending and the U.S. citizen resides in the U.S. Here is a common example.
Sam and I have a question about him visiting after the NOA2 has been approved. He is planning on coming the first week of June and we want to know if this will be an issue. He came back in February with no problems with POE of LAX. We would value your opinion in this matter. He still has ties to England with his business and such so he could supply evidence if prompted.
Sheryl, Yes, this is an issue. He is an intending immigrant and so there is an inherent risk he may overstay his welcome as a visitor in the U.S. Immigration officers are trained to block entry. He will need to overcome that presumption. Whether or not he succeeds depends on the officer who interviews him at the POE and luck.
There is generally no harm in trying as long as he is open and honest about his intentions and is prepared to withdraw if there is a problem. On a rare occasion, an immigration officer will not allow him to withdraw, but will instead accuse him of appearing for inspection without a proper immigrant visa and seek to bar him from the U.S. This would be an improper use of summary deportation procedures, but I have seen it happen. We would then need to argue to set the bar aside. As long as he is open and honest when presenting himself to a border agent and a border agent does not fabricate facts, then we should be able to lift a bar if necessary. Please consider and use your best judgment. Try to remain outside the U.S. unless it is important.