Trump threatens to retaliate against Democrats over investigations

President Donald Trump, in a fiery post-midterm press conference Wednesday, insisted he "stopped the blue wave," referring to the expectation of big Democratic wins.

"It was a big day yesterday, an incredible day and last night the Republican party defied history to expand our Senate majority while significantly beating expectations in the House for the" midterm year, Trump said. "I thought it was very close to complete victory."

But he also fired off what rang out like warning shots for Republicans who hesitated to embrace Trumpism and House Democrats who have threatened a flurry of investigations. The president also tangled with reporters in testy exchanges about his rhetoric on the campaign trail and messaging towards the migrant caravan which some critics say was racist. Still buoyed by what he viewed as successful midterm results, Trump scoffed at the potential for a legally messy year with Democrats controlling the House.

The president said if Democrats open up investigations into his personal finances and taxes, he threatened to take on a "warlike posture."

"I hear about investigations - fatigue. They've been giving us this investigation fatigue. It's been a long time. They've got nothing," Trump said. "They can play that game but we can play it better. It's called the U.S. Senate," the president added.

Democrats say they hope to subpoena the president for his still unreleased tax returns.

When asked to say point blank whether or not he would turn over his taxes, the president said he would consider if he still weren't under audit.

"If I were finished with the audit, I would have an open mind to it," Trump said in response to a question for ABC News' Jonathan Karl. Trump said he will wait until after the audit is completed.

The president expressed frustration with special counsel Robert Mueller's investigation and said he could end the probe "right now."

"I could fire everybody right now. But I don't want to stop it. Because politically, I don't like stopping it," Trump said. "I let it just go on. They're wasting a lot of money."

Trump, who has frequently said he is disappointed in Attorney General Jeff Sessions, said he would answer a question about firing Sessions and potential Cabinet changes at a "different time."

"We are a hot country. This is a hot White House," Trump said. "We are a White House that people want to work with."

At one point, the president told CNN's Jim Acosta, who asked about the inflammatory campaign ad about undocumented migrants that was pulled by major television networks, "I think you should let me run the country, you run CNN." The president -- visibly angered by being asked about the caravan -- told Acosta to "put down the mic."

That fiery tone was questioned by reporters in the room who cited the divided nation. The president said he would like to have a better tone, but pointed his finger at the media.

"I'd be very good at a low tone, but when things are done not correctly about you," Trump said, "you have to defend yourself. It's much easier than what I have to do. Going around is much easier than facing someone when you're being treated unfairly. You know what, when you have to fight - all the time fight - you really can't do lower."

The president has credited his constant campaigning and endorsements to the success of election night Republican wins. In the final days of the midterm election, Trump crisscrossed the country stumping for the GOP. He said one of the reasons Republican seats flipped to Democrats was that he could not campaign everywhere.

"President Obama campaigned very hard in Georgia. Oprah Winfrey campaigned very, very hard all over the television. I said that this is going to be tough. I only had me. I did not have anybody else," Trump said.

However, Vice President Pence, his son Donald Trump Jr., and Republican surrogates, including Sen. Lindsay Graham of South Carolina, campaigned.

In a shocking political moment standing at the podium from the East Room, the president mocked Republicans who did not embrace him and lost.

"They did very badly," Trump said. "I'm not sure if I should be happy or sad."

He then called out losing Republican members by name for rejecting his support.

"Mia Love gave me no love and she lost. Sorry Mia," Trump said. He also called out Republicans in swing districts like Barbara Comstock in Virginia and Peter Roskam in Illinois.

Despite losing the House, the president said he thought the election proved he was popular.

"I think people like me, I think people like the job I'm doing," Trump said.

Trump earlier took to Twitter to congratulate Republican winners, to bid adieu to Republican losers who didn't embrace him and to say that now he has a clear path toward "foreign nations (friends) that were waiting me out, and hoping, on Trade Deals.""Those that worked with me ... did very well," the president tweeted. "Those that did not, say goodbye!"As was widely expected, Democrats took back the House and Republicans maintained their Senate dominance.Americans elected the first Muslim and Native American women among a record 110 women projected to join Congress.There are many potential takeaways from Election Day 2018. Here are a few of the president's from Wednesday morning:

When the new Congress begins in early January, it will look quite a bit different to the president.

"President Trump has been eroding the foundations of our democracy," Rep. Elijah E. Cummings, D-Md., the ranking mMember of the House Committee on Oversight and Government Reform, said in a statement released Wednesday. "He has been degrading the vision of our Founding Fathers -- from attacking the right to vote to undermining the freedom of the press.

"Yesterday, the American people voted to change that. They voted for transparency and accountability. They voted to make sure our government works effectively and efficiently for the American people. And they voted to bring integrity back to government. As part of that mandate, I plan to shine a light on waste, fraud, and abuse in the Trump Administration. I want to probe senior Administration officials across the government who have abused their positions of power and wasted taxpayer money, as well as President Trump's decisions to act in his own financial self-interest rather than the best interests of the American people."