Independence Day on Thursday - as well as President Trump's recent visit to the UK and the Republic of Ireland - prompt the question of how important is the US to the Northern Ireland economy.
According to Department for the Economy analysis, during 2003/4 to 2015/16, the amount of US Foreign Direct Investment (FDI) supported by Invest NI was £1.5bn and represented 13,900 jobs promoted.
This was 35% of the total value of Invest NI-supported external investment during that period: "external" defined to include Great Britain.
Canada was the source of around 21%, Great Britain of 18%, the Republic of Ireland 8% and all others 18%.
The US provided a similar proportion of all jobs promoted by external investment, at 37%. Of all the foreign-owned businesses in NI the greatest number are owned by businesses in the Republic of Ireland, but on average the American-owned firms are larger in size.
NI, Invest NI in particular, has been especially successful in attracting US-origin service companies.
A great deal of attention has been focused on the film and TV production sector in Northern Ireland.
Growth in that sector owes a lot to US origin production companies and shows. It is important, however, not to exaggerate the absolute size of this sector - not that many people in NI are actually employed in making, say, Game of Thrones or Line of Duty.
According to the Quarterly Employment Survey, total employees in SIC code 59 sector Motion Picture, video and TV programme production increased 42% during 2008 to Quarter 1 2019, which does sound impressive compared to growth in the number of all employees in NI of 6.1%.
However, the growth in actual numbers in the film and TV production sector was about 500, ie from 1,240 to 1,760.
Employment in that sector represents only a fifth of 1% of total NI employee numbers, or two people in every 1,000.
If it assumed that 10% of the tourist sector employment growth during 2008-2019 can be attributed to film and TV production then that would add another 700 jobs.
In 2016, using HMRC data, the US was the destination for 24.6% of NI exports of goods.
This was the second largest export market after the Republic of Ireland which was 27%.
There is some evidence that the "technology/knowledge intensive" parts of the NI economy - aircraft, pharma and ICT - are more tied into the US market than to the EU27.
America does represent an important tourism market for NI but this should be kept in perspective. In 2018 US visitors spent £72.7m or 8% of the total spend by all overnight visitors (including those from NI).
This was more than three times the spend by Canadian tourists and almost as much as the total spend by all visitors from Continental Europe.
By comparison, 11% of total visitor spend came from the Republic of Ireland and 34% from Great Britain.
The US economy has been in relative decline for some time - this does not mean that it has stopped growing but that it has been growing more slowly that many other countries. It is doubtful if the Trump administration will be able to reverse this long run historical trend.
In 2014, according to the most accurate system of measurement, China overtook the US to become the world's largest economy.
The US connection still matters but not as much as it once did.
FDI and tourists are, increasingly, coming into NI from the wider world, notably China and India.
That trend is likely to continue.
In the context of Brexit, issues like the European customs union and single market and NI's connections to Europe have been to the fore.
It would be wise to balance that with some emphasis on the American links, especially given that the US market is particularly important for the higher technology sectors in NI, but those connections are also subject to flux and change.
Such flux is illustrated by the defence and aerospace sector in NI which is dominated by the Canadian-owned Bombardier plant - which is now up for sale - but with the relationship of the latter, whether collaborative or competitive, to both Airbus and Boeing being crucial.
Economic policy making should be about allocating scarce resources to get the best possible returns. Policy makers in NI have the dilemma of deciding how much they should invest to promote/maintain the economic ties to the US.
Should we be prepared to subsidise any restored direct air route connection? Should we try to compete with the Trump corporation tax reductions?