This item by J.P. Green was first published on July 2, 2010.
Rhodes Cook, senior columnist at Larry J. Sabato’s Crystal Ball, has some encouraging observations for Democratic candidates’ mid term prospects. Cook sees 2010 Dems in much better shape relative to the 1994 disaster. First, it’s about exposure, says Cook:

Fully half of the Democratic seats in that strongly anti-incumbent, anti-Democratic election 16 years ago were in districts that had voted for the Republican presidential ticket in one or both of the previous two presidential elections. This time, just one third of Democratic seats are in similarly problematic territory.
It is an important distinction since the vast majority of House seats that the Democrats lost in 1994 – 48 of 56, to be precise – were in “Red” or “Purple” districts. And this year, the Democrats have fewer of such districts to defend…The number of “Blue” districts they hold has risen by 43, from 128 in 1994 to 171 today, while the number of “Purple” districts they must defend has dropped by 39 (from 77 to 38). Meanwhile, the total of “Red” districts occupied by House Democrats is down this year by four from 1994 (from 51 to 47).

Even in 1994, notes Cook, “House Democrats ran very well in “Blue” districts that year. They lost barely 5% of those that voted for the party’s candidate in the previous two presidential elections.” If that pattern holds in November, Dems should keep their House majority.
Second, Cook sees Dems as “a more cohesive, top-down party than they were in 1994,” and adds,

Now, the Democrats have the look of a much stronger party. They are coming off a string of five consecutive presidential elections since 1992 in which their candidate has swept at least 180 districts each time. The byproduct of this consistent top of the ticket success has been the creation of more hospitable “blue” districts for House Democrats than their colleagues enjoyed in 1994.

Third, Cook finds encouragement for Dems in the House “special elections”:

But in recent decades, if a “big wave” election was brewing, there were signs of it in the special House elections that preceded the fall voting. That was the case in early 1974, when Democrat John Murtha scored a special election victory for a Republican seat in western Pennsylvania that proved a precursor of huge gains for his party that fall.
It was also the case in early 1994, when Republicans picked up a pair of Democratic seats in Kentucky and Oklahoma. And it was the case again in early 2008, when Democrats peeled off a trio of Republican seats in Illinois, Louisiana and Mississippi.
This election cycle, Republican Scott Brown has already scored a conspicuous special Senate election win in Massachusetts. But Republicans have been unable to post a similar high-profile breakthrough on the House side in spite of a handful of opportunities.
To be sure, Republicans did pick up a previously Democratic seat May 22 in Hawaii, where the incumbent had resigned to focus on his campaign for governor. But the victory by Republican Charles Djou was clearly a fluke. In a district that Obama had carried in 2008 with 70% of the vote, Djou prevailed with less than 40% as two major Democratic candidates divided the bulk of the remaining votes. There was no provision for a runoff election.
Much more noteworthy have been the special elections held over the last year in a trio of “Purple” districts. Republicans were unable to win any of them. Two were in upstate New York, the other Murtha’s seat in southwest Pennsylvania.
A GOP victory in the latter contest on May 18 would have been a loud reminder of 1974 – rekindling memories of how Murtha’s special election victory served as a harbinger of his party’s great success that fall.
That the vote last month was a loss for the Republicans, though, underscored the opposite – that winning a House majority this year might not be nearly as easy for the GOP as many political observers have predicted.

As Cook concludes, “…There are plenty of targets for the Republicans this fall. But there are not as many ripe ones as was the case in 1994.”