Trump frustrated as White House effort to defy impeachment inquiry fails to halt witness testimony, advisers say

After weeks of dismissing the impeachment inquiry as a hollow partisan attack, President Trump and his closest advisers now recognize that the snowballing probe poses a serious threat to the president — and that they have little power to block it, according to multiple aides and advisers.

The dawning realization comes as Democrats rapidly gather evidence from witness after witness testifying about the pressure put on Ukraine to investigate Trump’s political rivals. The president is increasingly frustrated that his efforts to stop people from cooperating with the probe have so far collapsed under the weight of legally powerful congressional subpoenas, advisers said.