BARACK OBAMA'S re-election hopes were dealt a setback by Mitt
Romney's relentless attack on his economic record at Wednesday's
presidential debate. Today, he got a lifeline from an unlikely
source: the economy.  In September, the unemployment rate
plunged, unexpectedly, to 7.8%, from 8.1% in August. It was the
first time it fell below 8% since January, 2009, the month that
Mr Obama took office. More important was the reason it fell: not
because people were quitting the labour force, but because they
were finding work, by remarkable numbers.  Non-farm payroll
employment rose by 114,000, an unremarkable number in itself and
pretty close to Wall Street's expectations. But the two prior
months were revised up sharply. Payrolls rose 142,000 in August
and 181,000 in July, a cumulative 86,000 more than first
reported. That, however, is not the full story. The Bureau of
Labour Statistics measures jobs two ways: the well-known payroll
survey of employers, and the lesser-known survey of households,
which yields the une