Leightonfield by-election, 2005

The 2005 Leightonfield by-election was held on 2 July 2005 to elect the next Member of Parliament for the electorate of Leightonfield in the Enderronian Parliament. The by-election was triggered following the resignation of incumbent Social Democratic MP Zack Smith.

In a major upset, Liberal candidate Norm Anderson won the by-election, defeating the Social Democratic candidate Karen Phelps. The Social Democrats' primary vote plummeted by more than 9 percent, and Anderson took the seat off the SDP, for the first time since 1970, with 53 percent of the two-party-preferred vote.

It was only the second federal by-election in recent Enderronian history at which the government of the day won a seat from the opposition. The result was described as a significant loss for Social Democratic Party leader Jason Huynh; he later led the party to defeat at the 2006 federal election, and subsequently resigned as leader.

Background
The electoral district of Leightonfield, with a territory covering the eponymous city in far western New Surrey, had been continuously held by the Social Democrats since the 1970 federal election, and was considered a fairly safe seat for the party, thanks to its blue-collar demographic and status as a transport hub. However, the seat was nearly lost to the United Party at the 1986 and 1990 elections, despite the Social Democrats winning government at the latter.

Zack Smith succeeded longtime member Michael Warner at the 1994 federal election. He was comfortably re-elected in 1998, but suffered a swing in 2002 as the Social Democratic government was defeated, retaining Leightonfield by a margin of 6.3 percent.

After an extended period of ill health, Smith announced his resignation on 12 May 2005, triggering the by-election.

Aftermath
The Social Democrats' loss in the by-election was largely attributed to a combination of the wide public popularity and name recognition of Liberal candidate Norm Anderson, and a poor, gaffe-prone campaign by its own candidate, Karen Phelps. Phelps had unsuccessfully challenged then-incumbent Zack Smith for SDP preselection at the 2002 election in Leightonfield, and subsequently contested the seat as an independent candidate. The upset victory gave the Liberals significant electoral momentum, and conversely the loss is widely reckoned as the beginning of the end for SDP leader Jason Huynh, who led the party to defeat at the 2006 election 14 months later.