US Defence Secretary James Mattis and Secretary of State Mike Pompeo will be arriving in India on 5 September for the first ever 2+2 dialogue between India and the United States.

As part of the dialogue, Mattis and Pompeo will meet Defence Minister Nirmala Sitharaman and External Affairs Minister Sushma Swaraj on 6 December at New Delhi.

The ministers and the US secretaries will hold wide-ranging talks over strategic, security, foreign ties and defence cooperation, including counter-terrorism and sharing of information, between New Delhi and Washington.

During the highly-anticipated meeting, which was cancelled twice in the past 14 months, the focus may be on the pending defence enabling cooperation known as Communications Compatibility and Security Agreement (COMCASA).

According to reports, the COMCASA, which aims to facilitate interoperability between US and Indian defence forces through transfer of communication equipment, may get “in-principle nod”.

Reports say that trade, Indo-Pacific convergence, Iran sanctions, situation in Afghanistan and Pakistan, China, military to military cooperation and designated terrorist tags for more terror organisations could be discussed in the meeting.

One of the most important subjects is likely to be India’s S-400 missile defence deal with Russia. Washington has been opposed to the deal and New Delhi is seeking a waiver on the deal.

The subject is expected to come up during the 2+2 dialogue ahead of Prime Minister Modi’s meeting with Russian President Vladimir Putin in October this year.

The dialogue was mutually announced by the two countries last summer, after Prime Minister Narendra Modi’s successful meeting with Trump.

Read More: What is ‘2+2 dialogue’? Here is everything you want to know

A ‘two plus two dialogue’ is a term — adopted in foreign parleys — used for installation of a dialogue mechanism between two countries’ defence and external affairs ministries. To put it simply, ‘two plus two dialogue’ is an expression used to indicate that two appointed ministers from each country, the ministers of defence and external affairs in this case, will meet up to discuss the two countries’ strategic and security interests. The goal is to establish a diplomatic, yet fruitful, conversation between the two countries’ respective heads of defence and external affairs.

Even though there is a tonne of expectations from this mutual dialogue between the two countries, the dialogue is also the source of some worry.

The US has always been sceptical of India’s mammoth oil import from Iraq. In the past, oil trade with Iraq has been a sensitive topic for both the countries, which this meeting is bound to bring up.

Another problematic pointer is India’s voluminous weaponry sanctions from Russia.