AS A matter of logic, the front-runners seeking the Republican presidential nomination should have welcomed a petition calling for guns to be allowed at the party’s national convention, to be held in Cleveland, Ohio from July 18th-21st, which drew more than 50,000 signatures. After all, Donald Trump says that the terror attacks in Paris would have been “much different” if more French citizens had been armed, while Senator Ted Cruz of Texas has denounced “gun-free zones” that turn the unarmed into targets for “lunatics”. Oddly, both men deferred to the Secret Service, which said no guns. Others sighed with relief, for this year’s Republican National Convention may be a brawl.

That marks a break with recent history. The main task of a national convention is to pick a presidential candidate, a choice made by delegates representing different states and territories. This year there will be 2,472 delegates—local worthies selected at state conventions or by party committees. Most delegates are “bound” in the first ballot, meaning they are allocated to a candidate by the results of a primary, caucus or convention back home. At every national convention since 1980 the winner was known before the first ballot, because a candidate arrived with a majority of delegates bound to him, turning the convention into a coronation. This year, if no candidate has secured 1,237 delegates then the voting could go on and on (see chart).

Trump backers insist that—should the businessman fall short of a majority but reach Cleveland with more delegates than any rival—there would be outrage if party “kingmakers” try to “steal” his nomination. Mr Trump himself has speculated about “riots”. The political context may be on Mr Trump’s side: this is, after all, an election cycle dominated by rows between the angry grassroots and a weak party elite.

The lessons from history are less clear. The party has held ten contested conventions. Only three nominated the candidate who initially boasted the most delegates. From the 19th century until the 1970s, Republican nominees were chosen after back-room deals between party barons and political machines, occasionally triggering fist-fights and furniture-smashing on the convention floor. Often the most important battles took place at state conventions and then in committee meetings in the days just before the convention, at which voting rules were set and the credentials of delegates loyal to one faction or other could be summarily revoked. The convention of 1880 went to 36 ballots, leaving all early favourites by the wayside.

Even today, convention rules are less like laws than the weapons with which political battles are fought. A rule of 2012, put in place by Mitt Romney’s allies to squash an insurrection by fans of Ron Paul, a libertarian, states that the presidential nomination is reserved for candidates who have won a majority of delegates in eight states. That bylaw, Rule 40, could stymie John Kasich and would prevent grandees from drafting Paul Ryan, say, as a last-minute nominee—unless the 2016 rules committee revokes it (a decision a majority of delegates would have to endorse).

John Hudak of Brookings, a think-tank, suggests that the real difference between 1880 and 2016 is that modern parties cannot build, fund and run a presidential campaign in the three and a bit months between the Republican convention and election day. That favours today’s two front-runners, Mr Cruz of Texas and Mr Trump. Both men are flawed national candidates, but both have established campaign machines. This year, convention delegates may face only bad options.