Trouble is brewing for Democrats in three true-blue strongholds that portend good things for Republicans in November's midterms, Newt Gingrich wrote in a column for Fox News.

Move over blue wave, this red wave is growing, writes Gingrich, who zeroes in on three trouble spots for Democrats:

New Jersey. Democratic voters are fed up with Sen. Bob Menendez, who may have lucked out with a mistrial on corruption charges but still must contend with the vapor trail. If Menendez loses, there's no way Democrats regain majority of the Senate.

California. John Cox earned a spot on the ballot for governor, which is predicted to increase Republican voter turnout by an estimated 23 percent. That bump will also help Republican House incumbents hold off myriad Democratic challenges.

Minnesota. Democrats are losing their minds there, ceding control to radicals who are left of crazy. "Ideological extremism has suddenly made Minnesota Democrats vulnerable," Gingrich writes.

Topping it off is the "growing and undeniable strength of the economy" under President Donald Trump.

"Americans are beginning to conclude that their lives are getting better, and that President Trump and Republican leadership are a part of that phenomenon," Gingrich writes.

"The result has been a collapse of the Democratic advantage in the generic ballot from a double-digit lead in December to some polls now showing Republicans on top. This is an enormous shift.

"I feel pretty good about my assertion that we are more likely to see a red wave than a blue wave on Election Day Nov. 6," Gingrich concludes.