The Dred Scott decision was significant because it ruled that:

The Dred Scott decision is a landmark Supreme Court case that fundamentally impacted the legal status of enslaved people and the broader context of slavery in America. The ruling declared that Dred Scott, an enslaved man who had sued for his freedom, could not bring a lawsuit in federal court because he was considered property, not a citizen. This affirmed the notion that enslaved individuals had no legal rights and thus could not sue for their freedom.

This ruling underscored the principle that under the law, enslaved persons were commodities owned by their masters, devoid of the rights typically afforded to citizens. The implications of this decision were far-reaching, further entrenching the institution of slavery and fueling tensions between pro-slavery and anti-slavery factions leading up to the Civil War, showing how deeply embedded the institution of slavery was in American society and law at that time.

The other options reflect important aspects of the conversation around slavery but do not accurately capture the core holding of the Dred Scott case. For instance, while the ruling did reinforce the primacy of property rights over individual rights, it did not ultimately make slavery illegal in all territories, establish owner discretion as a universal standard, or accurately represent how territories could approach the question of slavery.