Article snippet: WASHINGTON — The impeachment investigation into President Trump widened Friday into a constitutional battle between the executive branch and Congress, as Democrats subpoenaed White House officials and the president signaled his administration would not cooperate. Trump said he would formally object to the impeachment investigation, even as he acknowledged that House Democrats ‘‘have the votes’’ to proceed. Democrats warned Trump is ‘‘on a path of defiance, obstruction and cover-up’’ and said defying their subpoena would be considered ‘‘evidence of obstruction,’’ potentially an impeachable offense. The White House was expected to send a letter to House Speaker Nancy Pelosi arguing that Congress could not mount its impeachment inquiry without first having a vote to authorize it. The letter was expected to say the administration wouldn’t cooperate with the probe without that vote. Trump said the resolution would likely pass the House, but he predicted it would backfire on Democrats. ‘‘I really believe that they’re going to pay a tremendous price at the polls,’’ he said. Three Democratic chairmen — Reps. Elijah Cummings, Adam Schiff and Eliot Engel — warned Trump in a letter accompanying their subpoena, stating, ‘‘Speaker Pelosi has confirmed that an impeachment inquiry is underway, and it is not for the White House to say otherwise.’’ Trump’s comments came shortly before Democrats sent an extensive request for documents to Vice President Mike Pence about his contac... Link to the full article to read more