Nowadays, a candidate must believe not just some but all of the following things: that abortion should be illegal in all cases; that gay marriage must be banned even in states that want it; that the 12m illegal immigrants, even those who have lived in America for decades, must all be sent home; that the 46m people who lack health insurance have only themselves to blame; that global warming is a conspiracy; that any form of gun control is unconstitutional; that any form of tax increase must be vetoed, even if the increase is only the cancelling of an expensive and market-distorting perk; that Israel can do no wrong and the “so-called Palestinians”, to use Mr Gingrich’s term, can do no right; that the Environmental Protection Agency, the Department of Education and others whose names you do not have to remember should be abolished.