Final answer:
Obama represented the Democrat political party, also known as Democrats. The Second Party System consisted of Democrats and the Whigs, and the 1828 election marked the Democrats' first presidency with Andrew Jackson.
Step-by-step explanation:
Barack Obama represented the Democrat political party. This group of people is also known as Democrats, which can be correctly filled in for the question posed. They are sometimes referred to as liberals or progressives, but the actual name of the party is the Democratic Party.
The Second Party System in the United States consisted of the Democrats and the Whigs, not the Federalists and Democrats, nor the Democrats and Republicans.
The election of 1828 brought Andrew Jackson into the presidency representing the Democrat political party. This marked the beginning of the Second Party System.
It's important to differentiate between terms like liberals, progressives, and Democrats as these can have varying implications and historical contexts. While the term liberal has been widely used and at times ambiguously, progressives typically emerged around the turn of the century seeking reforms through government action to improve the conditions of society.