If Trump goes through impeachment proceedings, he would be judged by the 'court of public opinion'.  No problem with Demo congressman however only if big number of Republican constituents pressure their congressman to impeach Trump or lose re-election, would there be critical mass to start impeachment proceedings.  That is why it is so important for Trump & his staff to change the narrative & portray Comey as a lying, disgruntled fired worker skrum bag.  HOWEVER Comey is well respected& his testimony was masterful to lay the groundwork for impeachment.  Comey was only the initial probe attack against Trump but the real attack would be Mueller & his findings of obstruction of justice by Trump, Sessions for withholding a possible third meeting w/ Russians that he did not disclose & Jared Kushner with circumventing legal requirements in creating some "back channel" communications using Russians assets.   Like Nixon, Trump's only play would be to resign before impeachment.