Meet Carter Page - the former Trump campaign adviser who is at the center of the GOP memo controversy

AP

Carter Page

Carter Page, a former investment banker and campaign foreign policy adviser for Donald Trump's presidential campaign, is at the center of an intense debate over a classified memo that Republicans say exposes corruption at the highest levels of the FBI and the Department of Justice (DOJ).

The memo accuses top officials at the FBI and DOJ of misleading a federal judge in seeking a warrant to extend secret surveillance of Page during and after the 2016 presidential election.

But according to a Wall Street Journal report from Thursday, Page was known to US counterintelligence officials long before he ever joined the Trump campaign, dating back to at least 2013.

Here's what you should know about him: