Brodie first sought election to Parliament as a Liberal candidate in the October 1974 UK general election, standing in Dundee East. He contested that seat again in 1979. He had been selected to contest to contest Glasgow Hillhead for the Liberal Party at the next election; a seat the party was campaigning actively in. However, at the start of 1982, the incumbent Conservative MP Tam Galbraith died, triggering a by-election. The fledgling SDP, who had created an electoral pact - termed the 'Alliance' - with the Liberals immediately declared they wished to fight the seat and wanted Cabinet ministerRoy Jenkins to be their candidate. Critical of the fact that the SDP and Liberals were 'haggling only hours' after Galbraith had died, Brodie initially declined to comment on the situation, other than to indicate he would act in the best interests of the Alliance. Ultimately after talks with Jenkins in London, Brodie agreed to withdraw in his favour. Jenkins would go on to win the by-election. Following the merger of the Liberals and the SDP, he then contested Ayr in 1983 and North West Surrey in 1987. Brodie stood as a Liberal Democrat/SDP candidate in Surrey Heath'sOld Dean ward at the 1987 local election, finishing third with 475 votes. At the 1991 local election, he then stood in Surrey Heath's Bisley and Heatherside wards, finishing second and fourth respectively with 363 votes in Bisley and 879 votes in Heatherside. He fought Glasgow Garscadden as a Liberal Democrat at the 1992 general election, finishing in fourth place in the seat held by then-Shadow Scottish SecretaryDonald Dewar. Brodie was eventually elected in Surrey Heath's Parkside ward at the 1995 local election, coming second with 628 votes. Brodie stood as the Liberal Democrat candidate for Perth at the 1997 general election. At the 2001 general election, Brodie stood for the Liberal Democrats at Greenock and Inverclyde, finishing second with 5,039 votes. He then joined the Scottish National Party in 2010, first standing for them at the 2010 general election for Ayr, Carrick and Cumnock, where he finished in third place; moving ahead of the Liberal Democrats who took fourth.
Scottish Parliament
Brodie was an SNP candidate in the 2011 Scottish Parliament election. He was not successful in the constituency vote for Ayr, but was returned on the regional list as an MSP for South Scotland. At Parliament, he was a deputy convener of the Public Petitions committee and a member of the Economy, Energy and Tourism Committee and the Subordinate Legislation Committee. He was also Convener of the Cross-Party Group on Social Enterprise, and a member of the groups on China, Golf and Nuclear Disarmament. In 2013–14, Brodie claimed £54,297 in expenses, the highest amount for a MSP that session. In August 2015, he failed to win selection as the SNP candidate for the Ayr constituency, losing out to Glasgow councillor Jennifer Dunn. In October 2015, he was included on the SNP's regional list for South Scotland, placed seventh. The SNP returned three MSPs from their list.
Controversies
In March 2016, questions were raised about Brodie's Parliamentary expenses. Over the five years that he had been a MSP, he paid a total of £87,616 for "outsourced constituency work" to Caledonii Resources, a company set up in 2010. That company was 90% owned by Corri Wilson, who founded it one month before she became an SNP councillor for Ayr East ward in 2012. Some £20,000 was transferred during the Scottish independence referendum campaign in 2014 and a further £20,000 being transferred during the 2015 UK general election campaign.
In January 2017, Brodie resigned from the SNP and announced that he would stand as an Independent candidate in the Ayr West ward of South Ayrshire as part of the 2017 Council election. At the election, he secured 506 first preference votes, finishing last behind six other candidates.