John Roberts' confirmation seems like a lock. That is at least the conventional wisdom.

He has had remarkable bipartisan support. Last week, the Washington Post reported that "many Democratic lawmakers have expressed little interest in mounting a strong fight against Roberts, barring unexpected disclosures."

Just two years ago, in 2003, he was confirmed to the D.C. Circuit Court--often called the second highest court in the country--by a simple unanimous voice vote. He then sailed through the Senate Judiciary Committee by a 16-to-3 vote. Over 150 prominent members of the D.C. bar from both political parties wrote a letter to the Senate urging his confirmation to the Circuit Court. Even the left-leaning American Bar Association gave Roberts its highest rating at that time.

If history is any guide, Roberts will be confirmed, but Justice Sandra Day O'Connor shouldn't start moving back to Arizona any time soon. In fact, Roberts is likely to face a fairly difficult confirmation fight precisely because he is predicted be such an effective Supreme Court justice.

The last time a Republican president tried getting Supreme Court nominees confirmed through a Republican-controlled Senate was back in 1986, when it took Antonin Scalia 85 days and William Rehnquist 89 days. With the same length of battle today, President Bush will miss his hoped-for start date at the beginning of the Court's term in October by a couple of weeks.

However, that is probably overly optimistic. The confirmation process for circuit court nominees has dramatically lengthened over the last two decades: the average circuit court confirmation once took 53 days, but by 2003 and 2004 it had grown to 156 days--three times longer. If Supreme Court nominees will suffer the same three-fold lengthening of the process, Roberts' confirmation hearing could last well into spring.

Roberts' own history suggests that the process will be long. Of the 278 circuit court judges confirmed from 1977 through 2004, only five nominees took longer than the 729 days for Roberts to get confirmed between 2001 and 2003. (Indeed, the Democrats complaining that he has only been making judicial decisions for two years is a bit ironic because they would not hold a vote on his confirmation when he was first nominated in 1992 and delayed it again when he was re-nominated in 2001.)

It has usually taken longer for someone to get confirmed to the Supreme Court than the circuit court, given the additional importance of the position. Yet, in Roberts' case, that is unlikely to be true because the Democrats no longer control the Senate as they did during 2001 and 2002.

As expected, Democrats are lining up their talking points, such as whether Roberts was actually a member of the Federalist Society and whether he supposedly tried to hide that membership. Democrats are also blasting as insufficient the 75,000 pages of documents released so far from Roberts' tenure during the Reagan administration. Other Democrats are claiming that these initial documents show he is hostile to civil rights.

Issues from whether Judge Roberts properly answered questions about being a lobbyist in 2001, to whether he helped gay rights groups win a Supreme Court case in 1996, have also been added to the list.

Yet, new research that I have done indicates there is another reason besides these attacks to be concerned that this will be a long confirmation: the better a nominee's legal skills and the more successful the nominee has been as a lawyer, the more difficult the confirmation battle. Extremely intelligent, hard-working people make effective judges who write influential opinions and change the positions of others on the courts. That is the last thing one's political opponents want, and it helps explain why, despite rave reviews, it took so long for Roberts to be confirmed to the circuit court.

In studying all the circuit court nominees over the last five administrations, I found that résumé items that usually confer prestige have actually become more of a millstone than an advantage for those seeking judgeships. Many factors such as the type of legal work the nominee has done affect the length of confirmation, but Roberts' record of having graduated from a top 10 law school, serving on the law review, clerking for both the circuit and Supreme Courts, and having published scholarly as well as popular pieces will make his confirmation much more difficult.

Indeed, a nominee having a résumé like Roberts' faces a confirmation process that is on average more than twice as long. Being male and relatively young also lengthens the process. While there are not as many Supreme Court nominees to study, the results are very similar.

Survey data from the Almanac of the Federal Judiciary, which surveys lawyers who practice before circuit courts, suggest that the longer confirmation processes cannot be explained by nominees becoming more "extreme." Indeed, President Bush's judges are viewed as less conservative than Reagan's or the president's father's nominees. Indeed, despite their frequently difficult confirmations, Clinton's nominees were also not particularly extreme.

The difficulties in the most effective nominees getting confirmed aren't unique for judgeships. Robert Bork recently mentioned that he believed that Bush's nominee for Ambassador to the United Nations, "[John] Bolton is a victim of that, they fear that he would be too effective, that he simply would do too good of a job."

Merit should matter, and Americans presumably want the smartest, most influential people on our courts. But the next time you hear opponents claim that the president's nominee is "extremist," think "smart" instead.

John R. Lott Jr. is a resident scholar at AEI.