What would you want in a nominee? Of the ones most likely, which is the best? Who else would you pick?

President Obama faces a politically difficult choice about a new justice as the Supreme Court is at its own crossroads.

Liberal Justice John Paul Stevens, who announced Friday that he will leave the court this summer, has been a shrewd strategist at crafting majorities. In recent years, he has worked with swing-vote Justice Anthony Kennedy to blunt the force of the dominant conservatives. Though Stevens’ exit will not shift the ideological makeup of the court, it leaves a leadership vacuum on the left.

It also offers Obama an important moment to shape his legacy with a lifetime appointment on the highest court.

As Obama, a former constitutional law professor, confronts the decision, two basic paths lie ahead. He could choose a nominee likely to garner easy consensus among senators, such as U.S. Solicitor General Elena Kagan, 49, or Washington-based U.S. Appeals Court Judge Merrick Garland, 57. Alternatively, he could pick a liberal stalwart, such as Chicago-based U.S. Appeals Court Judge Diane Wood, 59.