Amazing what some major tax reforms and tax cuts in paychecks will do to public opinion.

A majority of Americans — a slim one, to be sure, but a majority nonetheless — believes members of the middle class now pay “their fair share” of federal taxes.

That’s way up from last year’s poll before Congress passed and President Trump signed the Tax Cuts and Jobs Act in December.

Under the ongoing tutelage of Democrats and media, a large majority of Americans knows that large corporations pay way too little in taxes, although — wait for it — the proportion that thinks they pay a fair share has also grown during the expanding economy and job markets of the Trump presidency.

Despite the enduring myth about those wealthy freeloaders, the fiscal reality is that the top 20 percent of U.S. earners pay 95 percent of all income taxes, which will be streaming onto the Treasury by the billions on today’s tax filing deadline.

But a new Gallup Poll finds that 51 percent of Americans now believes the middle class pays its fair share of taxes. That’s up from just 40 percent at this time last year.

Those numbers have basically reversed in the past 12 month, with 51 percent saying the middle class pays too much last year; now only 42 percent say that.

Last year 19 percent of Americans thought corporations paid their fair share in federal taxes. This year it’s 24 percent.

Overall, this is the most positive Americans have felt about tax fairness in a half-decade. The more optimistic feeling is due largely to improvements in the views of independents and Republicans. Democrats, of course, remain grumpy about the changes.

As for corporations, the increase in those believing they pay a fair share is due to Republicans and independents. In 2016, 22 percent of GOP members said corporations paid a fair share; this past year 31 percent did. Among independents, 15 percent said fair in 2016; today 24 percent.

As we wrote here previously, for a variety of intriguing reasons Americans have suddenly turned optimistic about the future of their country in general just in the past 16 months or so.