Which of the following was a major factor in preventing the Democratic Party from capturing the White House during the period 1868 to 1888?

While immigration policies were a topic of discussion, the Democratic Party did not consistently advocate for restrictive immigration during this period. In fact, many Democrats supported the integration of immigrants, particularly as they were often seen as a source of labor. Therefore, this stance is not a significant factor in the party's inability to capture the White House during these years.

Economic stability and growth during this time generally favored the Republican Party, which was associated with industrialization and economic progress. However, this condition alone does not explain the Democratic Party's struggles; rather, it was their historical context that played a more crucial role in their electoral failure.

Although foreign policy concerns existed, the fear of foreign aggression was not a predominant factor influencing the Democratic Party's chances in presidential elections. The party's domestic associations and issues stemming from the Civil War were far more pivotal in shaping public perception and electoral outcomes.