When Can We Show Donald Trump The Door?

From the Guardian in the UK:

Britain’s spy agencies played a crucial role in alerting their counterparts in Washington to contacts between members of Donald Trump’s campaign team and Russian intelligence operatives, the Guardian has been told.

GCHQ first became aware in late 2015 of suspicious “interactions” between figures connected to Trump and known or suspected Russian agents, a source close to UK intelligence said. This intelligence was passed to the US as part of a routine exchange of information, they added.

Over the next six months, until summer 2016, a number of western agencies shared further information on contacts between Trump’s inner circle and Russians, sources said.

In late 2015.  That was before Paul Manafort joined the Trump Campaign in late March, 2016.  That was before Carter Page was announced as part of Trump's foreign policy team (also March, 2016).

Before we go any further, the Guardian has this to say to our conspiracy-minded Trump defenders out there:

It is understood that GCHQ was at no point carrying out a targeted operation against Trump or his team or proactively seeking information. The alleged conversations were picked up by chance as part of routine surveillance of Russian intelligence assets. Over several months, different agencies targeting the same people began to see a pattern of connections that were flagged to intelligence officials in the US.

They were tracking Russian intelligence assets and then noticed that those Russian intelligence assets were talking to some Trump people.

Back to our story - Both Page and Manafort have been tied to various Russian intrigues in recent months.  So if it wasn't Page or Manafort, who in the Trump campaign was talking to elements of Russian Intelligence in late 2015? When were they talking? And what were they talking about?

How high up the campaign does the treason go?