Now it is a profession in its own right.
Fully one-in-six members of the Scottish Parliament has little or no experience of work life outside the world of public affairs, according to an analysis of the formative occupations of Holyrood members conducted by The Herald.
We found some 21 MSPs had been elected having spent almost all their working life in politics of one kind or another.
They include some of those hailed as a bright new generation of Scottish politics, such as the SNP External Affairs Minister Humza Yousaf or Labour education spokeswoman Kezia Dugdale, when they joined Holyrood in 2011.
In total, politics and public affairs added up to by far the most representative "formative occupation" of MSPs in Holyrood. Traditional gateways to a career in politics, such as law and teaching, were also highly represented. There were 11 lawyers, including Deputy First Minister Nicola Sturgeon, and 11 teachers, including opposition leader Johann Lamont.
Other white-collar professions remain well represented: there are two doctors; four social workers; four journalists; three accountants; five economists; two engineers; a scientist; a librarian; and an occupational therapist.
The Herald has listed MSPs as political professionals if they have little work experience outside politics, political PR or public affairs.
However, many older MSPs left their original "formative occupations" long before they were elected to work in what academics call politics-facilitating roles: typical full-time officers in think tanks or lobby groups; researchers for politicians or political parties; or public affairs PR. So some analysts who study the backgrounds of politicians have come up with higher figures than us for "political professionals".
These include Alex Wilson, Paul Cairney and Michael Keating, who recently completed a detailed paper on the backgrounds of politicians in all the legislatures of the UK. They calculated 33.1% of the 2011 intake came from the traditional professions, down from 51.2% in 1999.
And they found the number of MSPs they considered to have come from "politics-facilitating" roles such as full-time councillors, party workers and journalists and trade unionists had soared since the onset of devolution, from 18.1% in 1999 to 28.2% in 2011.
They concluded: "The professionals outnumbered the professional politicians by almost three to one in 1999, but they are now close to parity. Of the 2011 parliamentary contingent, 30% of SNP MSPs and 36% of Labour MSPS, have a formative occupation in politics-facilitating roles."