Italy's membership of the euro means that tackling the epidemic depends not just on ministers in Rome.
The European Central Bank (ECB) could help lenders continue to provide liquidity.
As this newspaper went to press, the ECB was expected to loosen policy,
either by cutting interest rates or offering banks cheap funding to lend to companies.
But, with its interest rates already at -0.5%, it cannot cut rates much further.
By contrast, both the Federal Reserve and the Bank of England have cut rates by 0.5 percentage points.
That means fiscal policy in Europe will have to do more work. But here Italy's public finances pose a complication.
Government debt is already high: in 2019 it exceeded 130% of GDP.
The extra spending means that Italy seems likely to exceed the European Commission's deficit ceiling, of 3% of GDP, this year.
In a sign that investors are fearing for the state of Italy's finances,
and perhaps nervous of a row with Brussels, yields on ten-year sovereign bonds have risen in recent weeks,
while those on German bunds have fallen. But if Mr Conte does not borrow more now,
the consequence will be a more prolonged downturn—and therefore a higher debt-to-GDP ratio in the long term, warns Mr Giavazzi.
That is perhaps why the European Commission says it will allow Italy to break its fiscal rules.
The commission plans to issue new guidelines on spending next week.
Emmanuel Macron, France's president, wants bolder action.
He is pressing for the rules to be suspended altogether, and for member states to co-ordinate spending increases;
that could shore up confidence that Europe will do what it takes to cushion the economic blow from the virus.
But Mr Macron's efforts have so far come to nothing,
because his counterparts in Germany and other northern countries prefer a wait and-see approach.
As the epidemic spreads, though, the advantages of a decisive response will only become clearer.