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An analysis of municipal by-election trends shows that the African National Congress (ANC) has been losing significant support and could bode ill for the party ahead of the upcoming local government elections (LGEs).

This is according to an analysis conducted by Gareth van Onselen, a veteran political commentator.

Van Onselen studied municipal by-elections since 2000 to determine various parties’ average support levels between the 2000 and 2006 LGEs, the 2006 and 2011 LGEs, the 2011 and 2016 LGEs, and the 2016 and 2021 LGEs.

He also looked at by-elections held since 2021.

In total there have been nearly 2 500 by-elections held since 2000, providing much data to determine various parties’ average support levels, particularly for the ANC, which had stood in nearly 2 400 by-elections in that period, far more than any other parties.

There are likely no more by-elections to be held before the upcoming 4 November 2026 LGEs.

According to Van Onselen’s analysis, the average levels of support (using a 12-month moving average) of the ANC has varied as follows:

• •The party’s average support in by-elections held between 2000 and 2006 was 55.4%;
• •Support dropped slightly to 55.2% for by-elections held between 2006 and 2011;
• •Support dropped to 48.9% for by-elections held between 2011 and 2016;
• •It stayed fairly steady at 47.5% between 2016 and 2021; and
• •Support for the party dropped sharply to 37.0% for by-elections held since 2021.

The party performed even worse in metro by-elections.

• •Between 2000 and 2006 the party’s average support level in metros was 53.5%;
• •This dropped to 43.3% between 2006 and 2011;
• •It dropped again, to 29.6%, between 2011 and 2016;
• •Support rose to 39.3% for by-elections held between 2016 and 2021; and
• •Support fell again to 24.0% for by-elections held since the 2021 LGEs.

The Democratic Alliance (DA) has seen its support level grow in the various election cycles:

• •Between 2000 and 2006 the DA’s average support was 39.0%;
• •This grew to 49.5% between 2006 and 2011;
• •It grew again to 51.7% between 2011 and 2016;
• •Support dropped to 38.5% between 2016 and 2021; and
• •Support grew to 45.9% for by-elections held since 2021.

For the DA, its average support in metros was as follows:

• •44.6% between 2000 and 2006;
• •This rose to 59.8% between 2006 and 2011;
• •It rose again, to 67.3% between 2011 and 2016;
• •It fell to 48.4% for by-elections held between 2016 and 2021; and
• •Support grew to 56.5% for by-elections held since 2021.

The Economic Freedom Fighters (EFF) was formed in 2013, meaning that the first municipal by-elections in which it stood were in the election cycle between 2011 and 2016.

Its average support level in municipal by-elections was as follows:

• •Between 2011 and 2016 EFF support stood at 10.0%;
• •This dropped to 9.7% between 2016 and 2021; and
• •It grew to 11.7% since 2021.

In metro by-elections the EFF’s average support:

• •Stood at 16.2% for by-elections held between 2011 and 2016;
• •Dropped to 8.8% between 2016 and 2021; and
• •Rose slightly to 9.0% since 2021.

Van Onselen also provided analyses of a number of other parties, including the Freedom Front Plus, the Inkatha Freedom Party, the Patriotic Alliance (PA), and the uMkhonto weSizwe Party.

These parties contested a fairly low number of by-elections, which means that any analysis should be approached with caution as the parties generally concentrate on by-elections where they are likely to perform well, and they do not participate in a large number of by-elections, while the ANC and EFF (and DA to a lesser extent) do.

However, the performance of the PA should be noted, with the party winning a fifth of the 129 by-elections it contested since 2021, with its average support level in these by-elections at 23.4%. It remains to be seen whether the party can replicate this support going into the 2026 LGEs.

Van Onselen argues that, because the ANC competes in the most by-elections, “its trendline is the most stable and powerful”. Historically, this has resulted in a strong correlation between the ANC’s by-election performance and its performance in local government elections.

For 2011, 2016, and 2021, the gap between the two was consistently around four points. (In 2011 its by-election performance was 4.1 points above its electoral performance, in 2016 its by-election performance was 3.8 points above its actual electoral performance, and in 2021 its by-election performance was 4.4 points below its actual election performance.) If that pattern holds, the model suggests the ANC should finish with between 31% and 39%. Other parties are harder to track in this way, as they are far more selective regarding which by-elections they contest and require comparative analysis.

The ANC has seen its support drop steadily in by-elections, which fits with its decline in support in national elections and LGEs, which is also reflected in its current polling levels. The party is likely to suffer its worst ever election in the November LGEs, and could be voted out of power in a swathe of municipalities across the country, including most of the metros.