Six months into his presidency, President Barack Obama is struggling to contend with increased public scepticism about his domestic agenda – including over the effects of the $787bn economic stimulus.

But even in the face of adverse opinion polls and objections from Congress he has stressed his intent to push ahead with his top legislative priority – healthcare reform.

He is due to hold a press conference tomorrow with a focus on that issue, his most cherished reform but one that is meeting resistance from fiscally conservative Democrats concerned about funding the estimated $1,000bn (€700bn, £600bn) 10-year cost.

Opinion poll findings in the Washington Post yesterday illustrated the scale of his task, with his own approval rating sliding in a month from 65 per cent to 59 per cent, and support for his healthcare drive subsiding from 53 per cent to 49 per cent.

In January 72 per cent of respondents said they were confident that his economic programme would improve the economy, the figure has now slid to 56 per cent. With concerns about the US federal deficit on the rise, only 35 per cent of those polled said they would support additional federal spending to revive the economy, with 61 per cent opposed.

Mr Obama has identified expanding health coverage to the more than 45m uninsured Americans as his biggest domestic project since before assuming the presidency and is seeking to convince both houses of Congress to vote on legislation before their August break.

That would pave the way for detailed negotiations about the text of the bill in the autumn. But his bid to increase popular backing for the initiative comes after a week of activity on Capitol Hill that left supporters of healthcare reform on the defensive.

Tomorrow’s press conference is also a test of the president’s own pulling power. Among the big US television networks, Fox declined to screen Mr Obama’s last prime time press conference, in April, and he held a subsequent press conference last month in the early afternoon, when it would not dislodge lucrative television programming.