The Labour campaign emphasised a strong economy; however, Blair had suffered a decline in popularity, which was exacerbated by the decision to send British troops to invade Iraq in 2003. Despite this, Labour mostly retained its leads over the Conservatives in opinion polls on economic competence and leadership, and Conservative leaders Iain Duncan Smith (2001–2003) and Michael Howard (2003–2005) struggled to capitalise on Blair's unpopularity, with the party consistently trailing behind Labour in the polls throughout the 2001–2005 parliament.