The US was a net exporter for most of the time it was a de jure and de facto reserve currency, up until the dollar was floated (i.e. end of gold convertibility). IOW, it was arguably the reserve currency status that drove the trade deficits, not the other way around. The effect was muted by the artificial constraint of gold convertibility, but the pressures from that restraint manifested in other problems, culminating in a currency crisis and Nixon's decision to end convertibility. That unleashed the deflationary pressures caused by reserved status, accelerating the shift to goods imports.

> The US was a net exporter for most of the time it was a de jure and de facto reserve currency, up until the dollar was floated (i.e. end of gold convertibility).

No, the US ran a goods surplus but a current account deficit.

If we look at US history, we can divide it into a few periods:

revolution to civil war: US is a net debtor, running goods deficits and borrowing from europe.

1870 - Great Depression/start of WW2: US is running goods surpluses (of about 1% of GDP) but continues to heavily borrow from Europe.

Post WW2 - Bretton woods. US is suddenly the world's biggest creditor, and it's good surplus rapidly declines to a deficit, forcing the US off the gold standard.

That middle period puzzled a lot of economists, because the balance of payments identity says that the current account plus capital account must sum to zero, so if the capital account is positive (continues to borrow from Europe) then the current account must be negative. But here we have reports of the US running a goods surplus! Well, the problem is that even though there was a goods surplus, the current account was negative. The US owed so much money in dividend and interest payments that the money earned from the goods surplus wasn't enough and the US kept getting deeper in debt to Europe throughout this period, which meant that Europe was a net accumulator of US liabilities even though the US ran a goods surplus.

And it was the fact that Europe kept accumulating US liabilities that allowed the these liabilities to be traded as an effective reserve currency. If the US was not getting its liabilities into the hands of the europeans, then there is no way US liabilities could possibly be used to settle international trade. This should be a no brainer.

Now a lot of crazy stuff happened during the stock market crash and capital flight during WW1 and WW2 that turned the table on the Europe, so the US ended up in a situation where, very suddenly -- as in, over the course of just a few days -- it became a net creditor to Europe, but that necessitated the Marshall plan, where the US needed to flood Europe with dollar claims -- which were gifts, not investments -- in order to prevent the European economies from grinding to a halt in the immediate aftermath of WW2, and then the US goods trade deteriorated so that we had to go off the gold standard. Thus the period from the end of WW2 to the end of Bretton woods should be viewed as an anomalous disequilibrium period of adjustment, and if you look at US current account data, you see a fairly rapid decline because the US goods surplus during the WW2 period was artificially inflated by counting munitions and war material as exports, but these exports were "paid" for by loans that were forgiven, and this, together with the Marshall plan, is what screws with traditional readings of the balance of payments identity in that WW2-end of Bretton woods period.

Bottom line, if you want to run trade surpluses and be a reserve currency, you need to be giving away more claims than are necessary to buy your goods, because at the end of the day, the rest of the world has to be a net accumulator of claims on you in order for those claims to be a reserve currency.