WASHINGTON — In rapid succession, six federal judges on two appeals courts weighed in on a key component of President Barack Obama’s health-care law. But, possibly even more importantly, their votes lined up precisely with the party of the president who appointed them. It was the latest illustration that presidents help shape their legacies by stocking the federal bench with judges whose views are more likely to align with their own. The legal drama played out Tuesday in Washington, D.C., and Richmond, …