In a dramatic victory for President Barack Obama, the Supreme Court upheld the 2010 health care law Thursday, preserving Obama’s landmark legislative achievement.

The majority opinion was written by Chief Justice John Roberts, who held that the law was a valid exercise of Congress’s power to tax.

The decision came as a sharp rebuff and disappointment to congressional Republicans, many of whom had expected the court to strike down at least some parts of the law.

Passage of the law in 2010 had come at a high political cost, with 14 House Democrats in competitive districts losing their seats in the 2010 elections in part due to their votes for the bill and six Democratic Senate candidates who’d voted for the bill also lost their elections in 2010.