Rep. John Boehner (R-Ohio) was reelected as House speaker, after a group of hard-right conservatives tried and failed to deny him another term. (AP)

Updated 3:03 p.m. Boehner lost the votes of 25 House Republicans, marking the biggest defection in at least 100 years.

Update 4:58 p.m. According to the book "Fighting for the Speakership," the last time this many members voted against a major-party's speaker nominee was 1860, when Republicans split their votes between two candidates: John Sherman of Ohio and Galusha Grow of Pennsylvania. Neither, though, was the incumbent speaker. Grow wound up winning.

The original post follows.

House Speaker John Boehner's GOP opponents will try to take him down Tuesday. They are fighting against both the odds and history.

The Ohio Republican faces reelection to his third term as leader of the House this afternoon, and he's expected to face at least token opposition from conservatives in his own party; the latest whip count shows as many as 18 members could oppose Boehner. But that's well shy of the minimum 29 needed to even bring Boehner to a second vote and throw his reelection into doubt — an outcome that still seems quite unlikely.

And not only is it unlikely, it's largely without precedent.

Rep. John Boehner (R-Ohio) was reelected to serve a third term as House speaker, but hard-right conservatives rallied in opposition. (AP)

The last time that an election for speaker even went to a second ballot was 92 years ago — in 1923 — when Frederick H. Gillett (R-Mass.) required nine ballots to win reelection as speaker, according to the Congressional Research Service. That was the only speaker election in the past century for which multiple ballots were even needed. And Gillett wound up winning.

In addition, in the half-century between 1945 and 1995, not one vote was cast for anyone but the two major-party nominees.

That's no longer the case, of course. Amid Newt Gingrich's issues in 1997, four Republicans voted for other GOPers and five voted "present" rather than support their incumbent speaker. Gingrich still won on the first ballot with 216 votes — three more than the 213 he needed.

Aside from a couple renegade votes in the years that followed, there weren't significant defections again until 2011, when 19 Democrats cast symbolic votes against outgoing speaker Nancy Pelosi (D-Calif.), who had already lost her post by virtue of losing the House majority in the 2010 election.

And finally came 2013, when a few members ditched both Boehner and Pelosi. Boehner still had enough votes (216) after the names were read the first time, and he eventually took home 220 votes.

The defections Tuesday appear as though they could be more significant than at any point since 1923, but Boehner has one major advantage amid the revolt: the GOP is tied for the biggest majority since the 1929-30 Congress. The GOP's 246-188 advantage means Boehner can lose 29 votes before we can even talk about him being in real trouble. That's because, were that to happen, the opposition would need to rally around a single alternative to have a chance.

The last time significant defections were common — in the 1910s, '20s and '30s — it was more common for other candidates to be officially nominated, often by progressive members who bucked the two major parties. Progressive members in 1923, for example, cast 17 ballots for Republican Rep. Henry Cooper (Wis.) and did so for eight straight ballots, depriving Gillett of his majority until the ninth ballot, when they relented.

Unlike 1923, the opposition today is hardly united, and the alternatives to Boehner who have stepped forward — Reps. Ted Yoho (R-Fla.) and Louie Gohmert (R-Tex.) — are hardly the type who will harness widespread support.

Which makes Boehner a heavy, heavy favorite Tuesday — even if it's the most interesting speaker race in 92 years.