A challenge to Libertarian

Arnold Kling is taking up the case that less government is better than more government.

Since I have been banned at his site I will respond here.

From 1850 to 1950 US trend per capita real GDP growth was 1.4%.

Since 1950 US trend per capita real GDP growth has been 2.1%.

From 1850 to 1950 modern capitalism dominated by the limited liability corporation dominated the economy and the only big difference in the two eras is the existence of big government since 1950. Yes, the data was less reliable in the earlier era, but I know of no reputable economic historian that disagree with the statement that real per capita GDP growth has been significantly faster since 1950 than in the previous century. Moreover, if you only calcualte the trned to the late 1920s you still only get the 1.4% trend. the depression and WW II do not distort this trend.

I would argue strongly that this factual evidence strongly contradicts the libertarian case and it is up to them to disprove or contradict this factual evidence.

Some libertarians argue that rapid emigration from 1850 to 1950 significantly dampened US growth. I seriously doubt this and have seen no evidence to support this argument and considerable evidence to contradict the argument. For example migration in the earlier era was heavily concentrated in the northeastern cities and real per capita income in these cities was much, much greater than in other parts of the country where the dominant economic activity was small scale agriculture. Do you have any evidence that a new Irish emigrant in Boston was poorer than a tenant farmer in Mississippi in the 1870-80s ? Second I am using per capita data and this would include small children that even in the 1800s did not contribute to real GDP. Among native born Americans such children would have accounted for a much larger share of the population than among recent emigrants.

So again, what is actual factual evidence that rapid emigration significantly dampened the growth of per capita real GDP in the earlier evidence?