“If you break it, you own it” is perhaps the least true truism in politics. Think George W. Bush, who launched the 2003 invasion of Iraq on spurious grounds, thereby unleashing a wave of turmoil in the Middle East that his successors may be dealing with for a quarter century or more. Closer to home, New Hampshire residents will recall House Speaker Bill O’Brien and his merry band of Tea Party pranksters who blew up the state budget following their ascension to power in 2010. Granite State voters came to their senses in the following election, choosing adults who could restore order out of the chaos created by O’Brien.

Now comes Boris Johnson, a Conservative member of Parliament and a former mayor of London, who deployed his considerable roguish charm as leader of the “Brexit” forces during the recent referendum on whether Britain should leave the European Union. When the results were tallied, Johnson seemed as astonished as anyone that voters had swallowed the snake oil he was peddling.

As it turned out, he not only didn’t have a plan B for what happens next; he didn’t have even a plan A. A few days after the vote, Johnson made the first substantive comment from the Brexit side in his column in The Daily Telegraph and began to backtrack furiously, in what struck a number of observers as a shoddily executed effort to counteract panic in the financial markets. Not long after that, Johnson bowed to reality and withdrew from the race to succeed Prime Minister David Cameron, who staked his career on Britain remaining in the EU. “He’s like a general who marches his army to the sound of guns, and the moment he sees the battleground abandons it,” Michael Heseltine, another Tory politician, said of Johnson. Sarah Lyall, in an acid “Memo From London” in The New York Times, wrote that, “As he abandoned  his campaign to be Conservative Party leader . . . he seemed almost relieved to be spared the burden of running the country he had done so much to destabilize.”

This debacle should serve as a cautionary tale to American voters beguiled by Donald Trump’s siren song. There are strong similarities between Johnson and him (although the former’s reputed charm and erudition are definitely not among them). For example, according to Lyall, Johnson’s “surface success has always carried alongside it a reputation for lies, evasions and exaggerations, a lack of seriousness and discipline, a tendency to wade into situations without thinking through their ramifications, and a perception that he puts his own ambitions first.” It is a sobering thought that if Trump, who shares so many of those traits, were to wake up the day following this November’s election as the president-elect, he, like Johnson, wouldn’t have a clue how to proceed. His proposals (if they can be dignified as such) on trade, tax cuts, immigration, abortion and gay rights would lead to chaos if pursued seriously. On the other hand, maybe he doesn’t mean them to be taken seriously. We can only hope American voters aren’t seduced, as the British were, by a charlatan.