Having grown up in an era when Republicans were seemingly condemned to permanent minority status in Congress, I have some sympathy for Democrats, who appear to be in a similar predicament today.
There were a number of factors that cemented the Democratic majority from 1932 to 1994 (interrupted only by 2 Republican congresses from 1946 to 1948 and 1952 to 1954, and Republican control of the Senate from 1980 to 1986).
First was an unholy alliance between conservative Southern Democrats and liberal Northern Democrats. This alliance was maintained by the seniority system in Congress, which allowed Southerners to chair many of the most important committees. Congressional seats in the South tend to be safer than those in the North, thus allowing conservative Democrats to gain seniority and power at the expense of their Northern liberal colleagues.
Second was Democratic control of state legislatures, which gerrymandered House seats in order to keep Southern seats in Democratic hands long after Republicans had gained substantial strength there. For decades, Republican representation in the House was much less than the percentage of votes cast for Republicans in all House races.
Third was money. Because Democrats controlled Congress, businesses had no choice but to contribute heavily to them, even though the party is fundamentally hostile to the business community. Businesses figured that contributions would at least buy them access so that they could minimize the damage of Democratic policies on their industries. Also, many businesses tended to hire Democratic congressional staffers for their Washington offices, who encouraged their bosses to contribute to Democratic campaigns.
Voters instinctively understood that Democrats had rigged the game in Congress, which is why they so frequently elected Republican presidents. However, while Republican presidents could block liberal initiatives, Democrats simply waited them out. Eventually, a Nixon would come along who was so desperate for re-election that he would sign almost any bill sent to him. Or they would wait for the occasional Democratic president, like Lyndon Johnson, to ram through massive new entitlement programs that were impossible to cut once in place.
The first break in this seemingly endless trend toward government expansion came in 1964, when Republican Barry Goldwater carried most of the South, even as he lost in a landslide. Southerners were becoming fed up with federal intrusion in their affairs and wanted to send the national Democratic Party a message. Fortunately for Republicans, that message was ignored.
In the 1970s, inflation and the rising taxes that went with it began to make voters more receptive to the Republican message of tax cuts and smaller government. Democrats could not respond without alienating their core constituency of those who benefit from government programs.
At the same time, the liberal wing of the party, flush from a big victory in the 1974 elections, destroyed the seniority system in Congress, pushing many conservative Southerners out of key chairmanships. This broke the deal that had kept Southern conservatives in the Democratic Party even as the party moved left. Without the benefits of seniority, there was no good reason for Southern conservatives to stay in the Democratic Party, opening the door to Republicans at the congressional level in the South.
Republicans were finally able to break the gerrymandering of congressional districts by forcing legislatures to create minority districts. This tended to create safe Democratic seats in the cities, surrounded by Republican seats in the suburbs. Of course, it was Democrats who had pushed through the Voting Rights Act that forced the creation of minority districts.
Concurrently, Republicans benefited from a decades-long effort to elect Republicans in state legislatures. After each decennial census, Democratic gerrymandering eroded, giving Republicans a fair shot.
The final piece of the Republican renaissance came when Republicans stopped giving a pass to conservative Democrats. Instead of allowing them to run unopposed, the party started to put up strong, well-financed candidates against them. This, plus abuse from the liberals who controlled the Democratic Party, led almost all conservative Democrats either to retire or become Republicans.
By 1994, the pieces all came together and Republicans took control of Congress. Now, they benefit from safe Southern seats, get 60 percent of business campaign contributions,and gain as well from the recently passed campaign finance legislation. It raised limits on individual contributors, which Republicans have more of, while restricting soft dollars, which Democrats had depended upon.
Thus we see that Republican control of Congress was the result of 30 years of effort to break down the Democratic advantage. But without Democratic missteps, it would not have worked. Similarly, it will take Republican missteps to give Democrats an opening to recover. The latter may elect a president from time to time, but they will likely remain in the minority in Congress for decades to come.