Washington (CNN) Favorable views of the Democratic Party have dropped to their lowest mark in more than a quarter century of polling, according to new numbers from a CNN poll conducted by SSRS .

Only 37% of Americans have a favorable opinion of Democrats, down from 44% in March of this year. A majority, 54%, have an unfavorable view, matching their highest mark in polls from CNN and SSRS, CNN/ORC and CNN/USA Today/Gallup stretching back to 1992.

The rating includes low favorable ratings from some core Democratic groups, including nonwhites (48%) and people under 35 years old (33%). The numbers come amid recent feuds and divisions in the Democratic Party, as former interim chair Donna Brazile's new book has unveiled new questions about infighting during the 2016 presidential campaign.

But the Republican Party isn't doing any better, with just 30% of Americans holding a favorable view. That's essentially the same as September, when the rating hit its lowest point in polling back to 1992 , but down from 42% in March. A broad 6 in 10, 61%, have an unfavorable opinion.

This means both parties sit at or near rock bottom as voters go to the polls across the country on Tuesday, most prominently in governor's races in Virginia and New Jersey, as well as dozens of local and mayoral races nationwide.

A substantial 33% of liberals and 41% of conservatives have unfavorable views of the Democratic and Republican parties, respectively. Plus, 4 in 10 independents, 42%, say they have an unfavorable view of both parties vs. only 8% who say they have a favorable view of both.

Indeed, a bare majority of Americans, 51%, say it's bad for the country that the Republican Party is in control of Congress. Only 38% say GOP control is good for the nation. That's worse than at any point in CNN's polling on the Democratic majority in Congress between 2007 and 2010.

A look ahead to 2018

But at least for now, all of those negatives for the GOP appear to outweigh the Democrats' decline in popularity when it comes to the ballot box, with Democrats continuing to hold a lead on a generic congressional ballot. Democrats top Republicans on that question by a wide 12 percentage points, 50% to 38%. That's similar to a 14-point gap between the two parties last month.

Republicans and Democrats remain almost unanimously united behind their own candidates in 2018, but Democrats hold a crucial 10-point lead among independents.

There are more warning signs for Democrats in this poll. Overall, 36% of registered voters who identify as Democrats or Democratic-leaning independents say they are extremely or very enthusiastic about voting next year, down from 44% who said so in September. That puts Democratic enthusiasm on par with that of Republicans, which stands at 37%.

And there are signs in the poll that more of next year's vote may be driven by dislike of a party than affection for one.

Sweeping majorities of voters have unfavorable views of the party they won't support in 2018: 87% of people who say they'd back a Democrat have an unfavorable view of the Republican Party, and 89% of those who say they'll back the Republican have a negative view of the Democrats.

Still, a sizable number view the party they do plan to vote for unfavorably: A third of voters on both sides, 32%, say they have an unfavorable view of the party whose candidate they say they'll support in 2018.

Trump's record unpopularity , now down to just 36% approval, also bleeds into the midterm elections: Roughly the same number, 35%, say they'd be more likely to vote for a candidate who supports Trump over one who opposes the president, down from 41% in April.

Americans say their own member of Congress deserves re-election in November, 46% to 39%, with a sizable 15% unsure. But two-thirds, 65%, say most members of Congress don't deserve re-election. Even among Republicans, who control both chambers of Congress, 51% say most members aren't worthy of another term.

The future of GOP tax reform

On the Republican tax reform plan, only 31% of Americans say they support the GOP tax reform proposals in Congress. Less than half, 45%, say they oppose the plans, down from 52% last month, when the question wording included Donald Trump's name. A quarter have no opinion on GOP tax reform plans.

Support for the tax plan overall is largely split down party lines: 64% of Republicans, 31% of independents and 8% of Democrats say they support the plan.

Only 21% say they will be better off under the GOP tax plan vs. 32% who say they will be worse off, similar to the divide in October before details of the plan were released. And by a two-to-one margin, Americans say it would increase the deficit instead of shrinking it, 40% to 18%.

Republican leaders in Congress have said they hope to pass sweeping tax reform legislation by the end of December, adding at least one major legislative accomplishment in their first year.

JUST WATCHED Poll: Americans concerned about Russia probe Replay More Videos ... MUST WATCH Poll: Americans concerned about Russia probe 02:05

Majorities of Americans oppose some core tenets of the GOP tax plan: 52% say they oppose lowering the corporate tax rate, 56% say they oppose repealing the estate tax and 52% oppose eliminating deductions for state and local income and sales taxes.

Still, majorities back some parts: a broad, bipartisan 79% say they support increasing the child tax credit and 55% say they favor increasing the standard deduction. About half of Americans, 49%, say they favor limiting the home interest deduction to only $500,000 worth of mortgage debt.

The CNN poll was conducted by SSRS by telephone Nov. 2 to Nov. 5 among a random national sample of 1,021 adults. The margin of sampling error for results among the full sample is plus or minus 3.6 percentage points; it is larger for subgroups.