Negotiating a trade deal is difficult – especially one like the Trans-Pacific Partnership Agreement that involves 12 countries, all with competing interests and agendas.
But that is not the end of it.
There is a big question mark hanging over US President Barack Obama's ability to win Congressional approval for any deal that his negotiators secure.
The President faces a Congress controlled by the rival Republican Party.
He needs to win the support of some of those Republicans to get the deal through Congress. That is because quite a few of the Senators and Representatives within the President's own Democratic Party oppose the deal.
Many Democrats are concerned about the same issues that have been raised here in New Zealand: drug costs, intellectual property rights and the potential ability of corporations to sue Governments.
Then there is the dairy issue. Some US politicians are anxious about what might happen if countries like New Zealand have greater access to the American market.
Every politician will be weighing up how the voters in their area view the deal.
The Congress cannot vote immediately on any deal.
Congressional rules mean that once a deal is agreed there is a waiting period of several months.
The trade negotiators must provide 30 days' notice to the Congress. Then the text of the deal must be placed on a public website for 60 days.
But there is also a waiting period of between 30 and 60 days where President Obama's negotiating team must submit a final legal text.
Only then can Congress can get to work debating and voting on the agreement.
By that point we are into 2016 and past the start of the US Presidential primary elections. They begin with the Iowa Caucuses on February 1st, followed by the New Hampshire Primaries on February 9th.
The elections will take place in an environment in which there are deep divisions – not just divisions between the two major parties, but also divisions within the parties.
That was made clear by the recent decision of House speaker John Boehner to retire. The Republican faced opposition from the tea-party faction of his own party. They felt he was too moderate and too willing to compromise with the Democrats.
The United States is not the only negotiating country facing elections soon.
Canada has an election on October 19.
Japan faces an election next year.
The New Zealand dollar starts the week little changed from seven days ago.
It gained 0.2 percent last week against the US and Australian dollars, rose 0.3 percent against the Euro and 0.6 percent against the British pound.
The Kiwi is trading at 91.30 Australian cents, 64.41 US cents, 42.44 pence, 77.28 Yen and 57.50 Euro.
It was a strong finish to last week for Wall Street, with the major indexes showing their biggest reversal in four years.
The markets were down around one and a half percent in early trading on Friday (Saturday morning New Zealand time).
But the Dow Jones Industrial Average rallied to finish up 1.23 percent at 16,472 points. The S&P 500 closed 1.43 percent higher at 1951. The Nasdaq gained 1.74 percent to finish at 4707.
The strong finish was despite weaker than expected US job numbers. The September non-farm payrolls report showed that 142,000 new jobs were created, well below the expectations of 203,000.
The European markets closed higher as well.
Germany's DAX rose 0.46 percent.
France's CAC 40 gained 0.73 percent and London's FTSE were up 0.95 percent.
The weaker than expected US jobs number has raised fresh doubts about whether the US Federal Reserve will hike rates for the first time in almost a decade.
The Fed's key lending rate is at virtually zero. There had been some people who expected a rate hike last month. That did not happen.
Instead many expected there could be an increase at the Fed's next meeting later this month. But the job numbers have given investors pause for thought, again. Many traders are now picking there will not be a rate hike until March at the earliest.
If there was an increase in the Fed's key lending rate it would raise the borrowing costs for businesses and people with a mortgage.
This could send the value of stocks down, but drive up the value of the US dollar. The dollar would rise as investors poured money into the US to take advantage of higher deposit rates.
The higher dollar would risk making US exporters less competitive.