Membership in an elite club — current senators who cast votes in the confirmation decisions for all the Supreme Court justices — nearly doubled with the death of Justice Antonin Scalia this month.

Nine sitting senators — six Republicans and three Democrats — can claim membership, up from only five who voted in the confirmations of all nine justices before Scalia’s death. 

A CQ Roll Call analysis of votes shows the senators always supported a nominee put forward by a president from their party. But the analysis also shows that Democrats appeared to become partisan earlier. The Democrats were largely following party lines by 1991, when all but one opposed the confirmation of Clarence Thomas.

Five Republicans, by contrast, voted for President Bill Clinton’s nominees: Justices Ruth Bader Ginsburg and Stephen G. Breyer. Sen. Richard C. Shelby of Alabama, a Democrat at the time, also backed Clinton’s nominees, but subsequently switched to the GOP.

Senate Judiciary ranking member Patrick J. Leahy of Vermont twice crossed party lines, voting for confirmation of Anthony M. Kennedy and John G. Roberts Jr. No other Democrat has backed a Republican nominee since.

The six Republicans — including Shelby by then — voted for Bush’s pick of Samuel A. Alito Jr. in 2006; all three Democrats voted against him. The reverse was true for confirmation of President Barack Obama’s picks of Sonia Sotomayor in 2009 and Elena Kagan in 2010.

Only five sitting senators were there to vote in Scalia’s confirmation in 1986 — Leahy and Republicans Orrin G. Hatch of Utah, Thad Cochran of Mississippi, Senate Judiciary Committee Chairman Charles E. Grassley of Iowa and Majority Leader Mitch McConnell of Kentucky.

The senators who join that list with Scalia’s death are Shelby, Harry Reid of Nevada, Barbara A. Mikulski of Maryland and Arizona Republican John McCain. All joined in the Senate in January 1987 and were there for the confirmation of the current longest serving justice — Kennedy.

The current Supreme Court justices are evenly split between Republican and Democratic appointees: President Ronald Reagan appointed Kennedy in 1988, President George H.W. Bush appointed Thomas in 1991, Clinton appointed Ginsburg in 1993 and Breyer in 1994, President George W. Bush appointed Roberts in 2005 and Alito in 2006, and Obama appointed Sotomayor in 2009 and Kagan in 2010.