President on the road to persuade voters economy is safe in his hands, ahead of elections expected to be tough on Democrats

Barack Obama is launching a campaign to persuade American voters that the ailing US economy is safe in his hands, ahead of November’s mid-term elections in which the Democrats are expected to receive a drubbing.

The president chose Milwaukee, a city in the manufacturing heartlands and home of the motorbike firm Harley-Davidson, to unveil a $50bn (£32bn) infrastructure package designed to boost jobs by investing in roads, railways and airport runways.

White House officials presented the scheme as a jump-starting of the economy that would put construction workers, welders and electricians back to work.

The speech is an indication that Obama intends to focus almost exclusively on the economy over the eight weeks up to the 2 November elections. His critics – including several representatives of his own Democratic party struggling to hang on to their seats – say this is not before time, and accuse the president of having dispersed his energies too widely on healthcare and foreign policy rather than concentrating on voters’ fears about their livelihoods.

Tomorrow marks the unofficial start to the campaign season, and there are signs of increasing urgency, if not panic, within Democratic ranks. The Cook Political Report, which monitors congressional races, predicts the Republicans stand to gain at least 35 seats in the House of Representatives, four short of the number needed to regain control, while a possible take-back of the Senate may also be on the cards for the party.

A recent Gallup poll gave Republicans a 10-point lead, the largest headway for the party ahead of the mid-terms since 1942 and double the advantage they held at the same time in 1994, when they snatched back Congress from the Democrats during Bill Clinton’s first term.

Obama’s infrastructure plan promises to rebuild 150,000 miles of roads, bring back to scratch 4,000 miles of railways and improve 150 miles of airport runways. It would also pay for the installation of a new air traffic control system and set up a permanent infrastructure bank to channel private and public money into projects.

The president will announce further job-creating schemes on Wednesday in Cleveland, including a plan to extend tax incentives for research.

The problem for Democrats is that none of these initiatives are likely to make a discernible difference before 2 November to the unemployment rate, which last month rose to 9.6%.

There is also an element of damned if he does, damned if he doesn’t. While Democratic candidates complain that Obama has failed to focus enough on the economy, Republicans suggest he has done too much, portraying him as an insatiable spender of public money.

As an indication of the likely campaign ahead, the Drudge Report, an influential conservative website, led today with the infrastructure package under a picture of Obama and the headline: “Addicted to stimulus – $50,000,000,000 more.”

With Obama’s presidential approval rating languishing at 45%, according to Rasmussen report, many Democratic incumbents are now openly avoiding any link with him. Some are barely mentioning their Democratic credentials on campaign literature.