While the expected "blue wave" of Democrat support did not appear on election night last Tuesday, some say it is gradually emerging.
The party has now won at least 32 seats in the House of Representatives, and leads in four more, with 10 contests too close to call.
They needed 23 seats to win the majority from the Republicans — and could get close to 40, according to some analysts.
The Democrats have also flipped seven governorships and eight state legislative chambers.
"Over the last week, we've moved from relief at winning the House to rejoicing at a genuine wave of diverse, progressive and inspiring Democrats winning office," Ben Wikler, Washington director of the liberal group MoveOn, told the Associated Press.
The Democrats found success by attracting support from women, minorities and college-educated voters. Fifty-six per cent of women nationwide voted blue, according to AP VoteCast.
That's bad news for Mr Trump, because those demographics are only growing, as the number of white males — the core support base he has courted — is steadily shrinking.
Arizona, Georgia, Texas and knife-edge Florida all have rising Latino populations, who could punish the President in 2020. Other states have, to a lesser extent, growing Asian populations.
The West and Southwest are all leaning left, and the Democrats also did well in the Rust Belt and Upper Midwest.
The Republicans gained two Senate seats, but this was in the largely rural areas, where they were expected to do well.
Mr Trump actually suffered the worst midterm results in the House for any Republican president since 1974, after Watergate.
2. MUELLER
In January, the Democrats will have the majority in the House. They will not only be able to vote down Mr Trump's legislation, they are also making plans to accelerate the investigation into alleged Russia collusion.
They also intend to hold hearings on Mr Trump's family separation policy, the sacking of James Comey from his job as FBI director, and the President's tax returns.
The party will have the power to subpoena Mr Trump and other White House staff.
Special counsel Robert Mueller is expected to issue more indictments this week as acting Attorney-General Matthew Whitaker settles into his new role as Jeff Sessions' replacement.
Mr Whitaker has been criticised for his denial of Russian meddling in the 2016 elections, and on Tuesday, his appointment was called "unlawful" in a court challenge by the state of Maryland.
Dianne Feinstein, top Democrat on the Senate Judiciary Committee, called for hearings into "the possible impact on Special Counsel Mueller's investigation".
Democrats, and even some Republicans, want legislation to protect the probe.
3. MONEY
The US economy has so far been relatively strong under Mr Trump, and his supporters credit it to him.
But the President's signature tax cuts have put the country on course for a deficit of $1 trillion a year.
The stock market had a bad start to the week with a huge sell-off, the Washington Post reported.
Economists predict slower economic growth, more market volatility and a recession. More than a third of top economic forecasters predict the US will enter recession in 2020 — just in time for the presidential elections.
"Based on the hand the GOP started with, they should probably have been able to retain the House," Michael Cembalest of JP Morgan Asset and Wealth Management said.
"Sometimes, however, money can't buy you love."
'DOUSED IN GASOLINE AND WAITING FOR A MATCH'
These are dark times for Mr Trump.
With white voters declining by several percentage points at every election, his strategy of ramping up fears over immigration and minority groups may be working against him.
His treatment of women has seen a serious decline in his support with female voters.
The investigations the Democrats have planned could expose new and embarrassing information of Mr Trump's presidential campaign, finances and even alleged affairs.
He may also disappoint over his supposed diplomatic success with Kim Jong-un, after the Centre for Strategic and International Studies yesterday revealed North Korea still had at least 13 hidden missile bases.
Of course, Mr Trump has always been good at fighting back in the face of dire predictions of his demise. But there is evidence he is feeling nervous.
On Tuesday, US media reported that he was preparing for a new White House shake-up, removing Homeland Security Secretary Kirstjen Nielsen and Chief of Staff John Kelly. First Lady Melania Trump called for changes to the National Security Council.
Mr Trump was not forthcoming on his plans. "We'll be talking about it," he said.
"This is how the President works," said a White House official.
"He's doused a bunch of people in gasoline and he's waiting for someone to light a match."
