WAUKEE, Iowa — As the impeachment inquiry swirls on Capitol Hill, Vice President Mike Pence is barnstorming around the country to attack impeachment-supporting Democrats in districts President Donald Trump won in 2016.

"I came to Iowa to turn up the heat," Pence said Wednesday from a stage in Waukee, Iowa. “The truth is Democrats have been spending all their time on endless investigations and partisan impeachment, but enough is enough — the American people deserve better.”

Pence took direct aim at Rep. Cindy Axne, the Democrat in the state's 3rd Congressional District who ousted a Republican incumbent, David Young, in the 2018 midterm election. With a farm as his backdrop, the vice president pressed for congressional approval of the United States-Mexico-Canada trade agreement, contending that Democrats calling for impeachment are sidestepping their obligations to the voters they represent.

“The time has come for Congresswoman Cindy Axne and all the Democrats in Congress that represent Iowa to put Iowa first, to put America first, and pass the USMCA this year," Pence said. "I’ll make you a promise: Whatever Democrats in Congress choose to spend their time on, President Trump and I are never going to stop fighting for you.”

The vice president will hold an event Thursday in Minnesota’s 2nd Congressional District, the home of newly elected Democratic Rep. Angie Craig. Pence will travel to Colorado and Wisconsin next week before making stops in the Democratically held districts of Reps. Abigail Spanberger of Virginia and Elissa Slotkin of Michigan.

The impeachment inquiry is likely to stall progress on other major congressional items as well. Just after House Speaker Nancy Pelosi announced the launch of a formal inquiry late last month, the White House said in a statement that Democrats in the chamber had "destroyed any chances of legislative progress" and were "in dereliction of their Constitutional duty."

While new polling shows a majority of registered voters support Trump's impeachment, the National Republican Congressional Committee, which works to elect Republican to the House, has claimed the issue has less support in the swing districts they're targeting.

Almost the entire House Democratic Caucus — including about two dozen of the 31 Democratic lawmakers in Trump districts — have called for some type of action on impeachment, according to an NBC News tally.

Meanwhile, the Trump administration has dug in against the Democrats' impeachment inquiry, putting up almost-universal resistance in its efforts to stymie the Democratic investigation into whether Trump used the power of his office to pressure Ukraine to investigate one of his political rivals, former Vice President Joe Biden.

Democrats have issued several subpoenas as part of the impeachment probe, including to Secretary of State Mike Pompeo and Trump’s personal lawyer Rudy Giuliani for documents related to the administration's Ukraine efforts. Lawmakers have also requested documents from Pence, but have not yet issued a subpoena for the material.

The impeachment inquiry centers on Trump's July phone conversation with Ukrainian President Volodymyr Zelenskiy, during which he asked Zelenskiy to "look into" the former vice president and his son Hunter Biden. Trump's decision to unexpectedly freeze almost $400 million in aid to Ukraine days before the call has led to allegations that he was attempting a quid pro quo arrangement, which Trump has denied.

On Wednesday, Pence demurred when repeatedly asked about his awareness of conversations within the Trump administration over the allegations that gave rise to the impeachment inquiry.