On 18 December 2003 Donaldson, Norah Beare MLA and Arlene Foster announced their resignation from the UUP and on 5 January 2004 they announced that they had joined the Democratic Unionist Party (DUP).
He is one of two Democratic Unionist MLAs for Fermanagh and South Tyrone alongside Arlene Foster, and was made a life peer in June 2006.
Jodie Foster | David Foster | Stephen Foster | John Foster Dulles | Al Foster | Norman Foster | Rube Foster | James Foster | David Foster Wallace | Arlene Francis | Foster and Partners | Norman Foster, Baron Foster of Thames Bank | Mo Foster | Lawrence Foster | Frank Foster | Ben Foster | Vince Foster | Frank Foster (musician) | Foster care | Arlene Phillips | Alan Dean Foster | Julia Foster | John Foster | Ian Foster | Hunter Foster | Ben Foster (actor) | Arlene Foster | ''The Wake Of Jamie Foster'' | Murphy J. Foster, Jr. | Kenny Foster |
The new call centre, and its potential for employment, received praise from Department of Enterprise, Trade and Investment minister Arlene Foster and Martina Anderson of Sinn Féin.
Notables to visit the wake included Cardinal Edward Daly; 1992 All-Ireland winning manager Brian McEniff; GAA President Christy Cooney, Northern Ireland's First Minister and deputy First Ministers, the Democratic Unionist Peter Robinson and Sinn Féin's Martin McGuinness; sports minister Nelson McCausland, enterprise minister Arlene Foster and justice committee chairman Maurice Morrow, Baron Morrow.
Victims groups and Unionist politicians including Democratic Unionist Party member Arlene Foster had asked the Parades Commission to ban the parade from the area where McElwaine was killed describing him as an "evil murderer", but the Commission ruled the commemoration could proceed without any restriction.