With congressional elections virtually upon us, public disapproval of the Democrats in Congress has hit a new high in ABC News/Washington Post polls dating back 20 years. And disapproval of their Republican counterparts - while not a record - is even higher.

Congress overall, for its part, has a 20 percent approval rating, one of its worst heading into a midterm election in polling dating back even farther, to 1974. With something there for nearly everyone to dislike, a bipartisan 77 percent disapprove of its job performance.

See PDF with full results, charts and tables here.

Evaluating just the Democrats in Congress, 67 percent disapprove, a high in polling since 1994 (albeit by a single point). Even more, 72 percent, disapprove of the Republicans in Congress, narrowly missing their all-time record for public scorn, 75 percent in January 2012.

The results sum up the public's broad political discontent and send another ominous signal to the Democrats, whose favorability rating, another measure of public sentiment, fell to a 30-year low in a recent ABC/Post poll. (The GOP again rated even lower, albeit not at a record low.)

While the Republican Party has weaker ratings overall, history suggests that the risk is more the Democrats', as the party that holds the presidency. From 1974 through 2010, using available data closest to each midterm election, approval of Congress has correlated with losses for the then-president's party at a substantial .63 (on a scale in which 1 is a perfect, positive match).

Congress was about this unpopular heading into a midterm twice before, with 18 and 21 percent approval in a pair of polls in October 1994 and 23 percent (among registered voters) in October 2010. Both times the incumbent president's party got nailed, losing 54 and 63 House seats, respectively. Analysts aren't suggesting anything like that kind of rout this year, given other dynamics - but the pattern marks the Democrats' risk, as do similar analyses, reported last week, correlating presidential approval and "wrong track" sentiment with in-party losses (.68 and .65, respectively).

This poll, produced for ABC by Langer Research Associates, suggests that things could be worse - a little. Congress' approval rating is up 8 points from its 40-year low after the partial shutdown of the federal government a year ago. The Republicans' 25 percent approval is 5 points better than their worst ever, in December 2011. And the Democrats' approval rating, 30 percent, is a non-significant three points from their low, also in December 2011.

Best for Congress, in a bleak situation, is that the intensity of negative sentiment is down from its peak - though, again, still high. While 50 percent of Americans "strongly" disapprove of the way Congress is doing its work, that's down from a record 70 percent after the shutdown a year ago.

AVERAGES - Comparison to averages also helps tell the story. Congress, in 126 available polls since 1974, has averaged 37-57 percent, approve-disapprove - unpopular on average, but less so than now (and with occasional forays into majority approval).

The Democrats and Republicans in Congress, in 34 ABC/Post polls since 1994, have averaged 40-55 percent and 31-64 percent, respectively. The Republicans thus are customarily more unpopular, as now - but the Democrats are a bit farther than usual from their average approval rating, and Congress overall, even more so.

GROUPS - Negative views of Congress, as noted, are bipartisan; roughly three-quarters or more disapprove across political and ideological lines. There are differences by age and race, with young adults and nonwhites less negative - but still broadly disapproving.

Predictably, partisanship roars back when it comes to approval of each party in Congress. What's most interesting is each party's weakness in its own base. A substantial 42 percent of Democrats disapprove of the way the Democrats in Congress are doing their jobs, and an identical number of Republicans say the same about the Republicans in Congress.

METHODOLOGY - This ABC News/Washington Post poll was conducted by landline and cell phone Oct. 15-19, 2014, in English and Spanish, among a random national sample of 1,004 adults. Results have a margin of sampling error of 3.5 points. The survey was produced for ABC News by Langer Research Associates of New York, N.Y.