Two voluntary calls have done nothing, now the Democrats in the US House of Representatives are setting the tone: under penalty of punishment, they have called on the government to hand over documents related to President Donald Trump's policy towards Ukraine. If the information is not available by 18 October, this will be considered as obstructing the investigation into the possible impeachment of Trump, said the chairmen of the three Trump investigating committees on Friday. Shortly before, they had requested documents from Vice President Mike Pence.

The measure threatens to aggravate the confrontation between the parliamentary chamber and the government: Committee chief Elijah Cummings had on Wednesday threatened with the motion, which now forces the White House to hand over the papers. Previously, it had ignored two letters requesting voluntary surrender. Therefore, they have now resorted to a call under penalty threat, a so-called subpoena, says the letter to Trump's acting chief of staff Mick Mulvaney. "We regret that President Trump brought us - and the whole country - into this situation, but his actions left us no choice but to issue this subpoena," wrote the three chairmen.

It was initially unclear whether the White House would bow to the subpoena. In the letter, MEPs explained in detail why the White House must bow to Parliament's control over this issue and not hide behind the privilege of government secrets. On Friday morning, however, President Trump had said on demand that if the White House would cooperate, the government's lawyers would have to decide.

The Democrats had been preparing for impeachment proceedings against Trump last week over the Ukraine affair. Trump came under pressure after it became known that he had encouraged Ukrainian President Volodymyr Selenskyj in a telephone conversation in late July to investigate his rival Joe Biden and his son Hunter. On Thursday, he also encouraged China to investigate. The Democrats see Trump's efforts to win the 2020 election with the help of a foreign government.