Graph "I think the broken promise line is doing the damage," said the Herald's pollster, John Stirton, of Nielsen. Any positive publicity over her trip to the United States last week was overwhelmed by the opposition's ferocious attack on Gillard, who told Channel Ten before last year's election that "there will be no carbon tax under the government I lead". She announced last month that she proposes to introduce one from July 1 next year. Her explanation is that circumstances have changed and she is working with a new parliament. The Labor minority government holds power at the pleasure of three independents and one Greens MP.

Gillard's consolation? Tony Abbott is also losing personal approval, is also losing to his main rival for his party's leadership, and remains well behind her as preferred prime minister. On the evidence of today's poll, conducted between March 10 and 12, voters have a strong nostalgic streak, preferring Kevin Rudd to lead Labor and Malcolm Turnbull to lead the Liberals. That was exactly the situation until December 2009. "The poll reflects that both party leaders are relatively unpopular following a period where both leaders were relatively popular," Stirton said. "Politics has become a lot more combative in the last 15 months and voters wish for a time when it was less so." In asking voters to choose their preferred Labor leader, the poll pitted Gillard against Rudd but also against two of the most often-touted next-generation Labor leaders, Greg Combet of the Labor Left faction and Bill Shorten of the Right. Both leaders are struggling with the voters. John Stirton, pollster.

Combet and Shorten won 9 per cent support each, with Gillard attracting 34 per cent and Rudd 39 per cent among all voters polled. Among Labor voters, Gillard was the most popular choice by a margin of 19 percentage points. In a closely parallel result, 23 per cent preferred Joe Hockey as Liberal leader, 31 per cent Tony Abbott and 37 per cent Malcolm Turnbull. Among Liberal voters, however, Abbott was preferred over Turnbull by a margin of 19 percentage points. "Both leaders are struggling with the voters," Stirton said. In today's poll, Abbott's approval rating has fallen by 3 percentage points to 43 per cent, while his disapproval is up by 3 to 52. This gives him a net approval rating of minus 9. Labor's primary vote is 33 per cent, a gain of 1 point over a month, statistically insignificant in a poll with a margin of error of 2.6 per cent. The Coalition's primary vote is 45 per cent, down 1 point, and the Greens are unchanged on 12 per cent.

Loading The election-deciding two-party preferred vote favours the Coalition by 54 per cent to Labor's 46, based on the pattern of preference flows at last year's election. This represents no change over a month. This two-party share of the vote appears to be unaffected by the eruption of the debate over Labor's proposed carbon tax. Only the standing of the leaders seems to have been affected.