Thomas and Scalia have been accused of undermining public confidence in the court by engaging in partisan politics and making decisions that could benefit the political and financial interests of their family and associates. And both justices have faced calls for the Justice Department to investigate alleged conflicts of interest and possibly to invalidate their votes in the 2010 decision on political spending, Citizens United vs. Federal Election Commission. One low-profile liberal watchdog group last week even asked the Missouri Supreme Court to disbar Thomas. Alito has been criticized for speaking at fundraising events for conservative groups opposed to Obama’s agenda. Only Chief Justice John Roberts, the fourth staunch conservative on the court, has been relatively immune from the same kind of criticism.

For liberals, the disposition – and, to some extent, the public perception – of the court is of looming concern as key aspects of Obama’s ambitious domestic agenda appear on a collision course with the Supreme Court’s conservative bloc, which has been able to lure swing Justice Anthony Kennedy on key cases, including Citizens United. Obama’s surprisingly blunt criticism of the majority’s decision in that case during his 2010 state of the union address seemed to set the tone for the scrutiny that followed.

“What we’re seeing is that there is major concern among liberals that the four died-in-the-wool conservatives on the court – with Justice Kennedy when they’re able to bring him on board – are now in a period of real activism,” said Noah Feldman, a Harvard law professor who wrote a book about the sometimes heated battles surrounding the jurisprudence of the liberal justices Franklin D. Roosevelt appointed to the Supreme Court.