In the United States, lynch mobs, at least as related to actual lynchings, did have an impact on politics. I’ll speak to a couple of examples at the state and federal level.

First, this answer relates to the period of history from Federal Reconstruction through the early 1940s in the United States. I can’t speak to other countries or other time periods in U.S. history, although lynchings before emancipation were largely regarded as “frontier violence.” I also can’t speak specifically to states other than Texas.

Second, this answer relates to lynch mobs of the type that conducted more than 4,700 lynchings in the United States between 1882 and 1968, according to the NAACP which is truly among the ultimate authority on this count because they were doing pretty meticulous tracking during this period.

There are multiple examples of the influence of lynching on American politics. Here are a few of the highlights.

White lynch mob violence provided some boost to federal Anti-Lynching legislation in the 1910s and 1920s. In fact, some would argue that Leonidas Dyer, whose name the Anti-Lynching bill ultimately bore, may have specifically been influenced by such violence near his district. [source here (https://history.house.gov/Exhibitions-and-Publications/BAIC/Historical-Essays/Temporary-Farewell/Anti-Lynching-Legislation/) ](That source has one of the more concise—without reading a journal article or book— of the descriptions of how mob violence impacted at least federal legislative politics in Congress during roughly 1917-1922. In its time, the Dyer act never passed.

The NAACP was the major driver of this movement. Pages of “The Crisis,” the group’s magazine, included many reports of lynchings over the years.

Lynching became a serious political issue, one considered by black voters and white voters alike, though perhaps for different reasons, in many parts of the country.

In terms of presidential politics, Theodore Roosevelt is probably the best example of lynching being interwoven with presidential politics.

Initially, Roosevelt condemned lynching.

Politically, it was a great deal of the basis of Roosevelt’s relationship with blacks in the years before the beginning of the shift of blacks from the Republican to the Democratic Party. (Ziglar, William, “The Decline of Lynching in America,” International Social Science Review, Vol. 63, No. 1, see especially p. 15 at II, is my preferred concise source; there are others.)

Roosevelt’s support ebbed and declined for a multitude of reasons. The refusal to pardon a black rape defendant who was believed insane further hurt his relationship with blacks. Pardons then we’re just as political as they are now.

When TR called for swift justice to aid in the decline of lynch mobs, he was heavily criticized in the black community and by the black press. One journalist noted Roosevelt had “sewn the seeds for a first-class lynching bee.” He ultimately became far less progressive on race, especially during a tour of the American South. (ibid, pp. 17-21).

Speaking to state politics, I can speak to Texas. Hopefully some other state level historians can chime in.

The Texas Legislature passed an anti-lynching law in 1897. The governor on occasion actually called out the Texas Volunteer Guard to prevent lynchings by protecting prisoners. (Source )

To give you a far more granular view, let’s look to Texas Gov. James V. Allred and this action of mob violence (a lynching) in Columbus, Texas. This was a later lynching, but one publicly condoned by local elected officials.

In the Allred Papers at the Texas State Archive (in Box 1985/024-21), which I examined in August of this year, there are +- 200 telegrams and dozens upon dozens of letters (I don’t have an exact count but I have scans of all of them) from around the nation (some from groups, college presidents, etc.) encouraging Allred to condemn the violence and or take action. There are about three letters or telegrams that favor the violence.

In the aftermath of that, Allred, who historians view today as progressive on race because of his reputation as an anti-Klan district attorney, publicly said he would order state law enforcement to investigate the incident. Were it not for the national media attention the lynching drew, it is debatable whether Allred would have done such a thing.

This incident also actually appears to show an example of a politician paying lip service to public sentiment following mob violence, as there is no evidence to suggest such an investigation was ever ordered in writing or undertaken by state law enforcement.

The incident did, however, influence San Antonio Republican Congressman Maury Maverick to become the only Congressman in the American South to support the Gavagan Anti-Lynching Bill in 1937. (Doyle, Judith Kaaz, “Maury Maverick and Racial Politics in San Antonio, Texas, 1938-1941,” The Journal of Southern History, Vol. 53, No. 2 (May, 1987), pp. 194-224.)

Lynch mob violence in the form of actual lynching did indeed have an impact on politics in the United States.