A senator has demanded that his former son-in-law, US Congressman Max Miller, resign over abuse allegations, saying he fears for the safety of his granddaughter. The demand, delivered in stark personal terms, places a sitting member of the House of Representatives under renewed public scrutiny.

The senator, who is the father of Miller's ex-wife, described the congressman as «dangerous» and said he should give up his seat. His appeal follows abuse claims made by Miller's former wife, who has accused him of threatening her with a gun and of injuring their daughter.

Miller has denied the allegations and remains in office. The congressman has rejected the account put forward by his ex-wife, and his denial sets up a direct confrontation with the senator, who is also the grandfather of Miller's child. The dispute now turns on competing accounts of what happened, with the word of a sitting congressman set against that of his ex-wife and her father.

The allegations at the centre of the dispute are serious. Miller's ex-wife has said that he threatened her with a gun and that the couple's daughter was injured during the alleged incident. The senator, speaking as the child's grandfather, said he fears for her and believes that the congressman should not remain in public office.

The senator's intervention is notable because it comes from within the family rather than from a political opponent. By speaking out in such direct terms, he has lent weight to the accusations against his former son-in-law while making clear that he considers the congressman unfit to continue serving. He has effectively aligned himself with his daughter's account against the word of an elected member of Congress.

The demand also carries wider implications for Miller as he carries out his duties in Congress. Calls for a member of the House to step down usually come from party leaders, ethics committees or political rivals; a resignation appeal from a former father-in-law is far more unusual, and it ensures that the allegations will continue to follow the congressman.

Miller has given no sign that he intends to comply. There has been no indication that the congressman is preparing to resign, and the two sides appear fixed in their positions: the senator insists that the allegations are credible, while Miller insists that they are not.

The case is a reminder of how personal conflicts can spill into public life when the people involved hold high office. For the senator, the matter is deeply personal: his daughter was married to Miller, and the child at the centre of the claims is his own granddaughter. His stated fear for her safety lies behind his decision to make the dispute public.

What happens next is unclear. The senator has made his position plain, describing Miller as a danger and pointing to his granddaughter as the reason for his alarm. Miller, for his part, has denied the claims and remains in his seat. The decision now rests with the congressman, whose future in the House has become the subject of an extraordinary appeal from a man who was once his father-in-law.