One likely reason that the debate over a potential Supreme Court nomination from President Obama is so fraught is that a third of the Senate has not been in office under any president other than the current one.

More than a quarter, in fact, have never been through the Supreme Court nomination process, as many arrived in the Senate after the last time one was confirmed. Nearly half of the Senate has never been through a court confirmation or has been through them only during Obama's presidency.

In fact, Congress on the whole is pretty new. When the next president is inaugurated in January, it will be only the second president with whom half of the House has served. More than half of that 435 members in the House took office since 2009. More than three-quarters were not around for the administration of President Bill Clinton. The largest class is 2010 House Republicans, predictably, followed by those that arrived after 2014. Most of the currently serving additions to the House and Senate since 2001 have been Republicans.

Only eight people in the Senate and five in the House — eight Democrats and five Republicans — pre-date the Reagan administration.

We've noted before that the Congress is at its most partisan. If there were ever halcyon days of comity between the two parties within the Capitol, it's safe to assume that very few of those who are now serving were around to remember them.