Chuck Grassley and other Republicans on the Senate Judiciary Committee have been arguing that the three vacancies on the DC Circuit should not be filled because the court's workload doesn't warrant it. They say the current number of eight active judges is sufficient, even though they pushed to fill the ninth, tenth, and eleventh seats during the Bush Administration at times when the court had fewer pending cases than it does today.
Since the numbers regarding pending cases don't support him, Grassley picks other numbers that he claims back him up, such as the number of cases filed in the previous 12 months. But he loses even there, making his hypocrisy even starker: In the spring of 2003, Grassley and other Senate Republicans supported filling the DC Circuit's ninth and tenth seats with John Roberts and Miguel Estrada. According to the Administrative Office of U.S. Courts, there were 1,077 filings at the DC Circuit in the year ending March 31, 2003 , with eight active judges. That is fewer filings annually than now  (1,141 for the year ending March 31, 2013), but with the same number of active judges, yet Grassley now insists that no more vacancies be filled.
So Grassley's argument falls apart even if you define caseload the way he prefers. That's because it isn't caseload that is really motivating Grassley, but desperation to hide the real goal : to prevent a Democratic president from fulfilling his constitutional duty to fill existing court vacancies.