Trump aides were in constant touch with senior russian officials during campaign

You're referring to the controversy surrounding the Trump campaign's alleged contacts with Russian officials during the 2016 presidential election.

In April 2017, it was reported that Trump's aides had been in constant touch with senior Russian officials during the campaign, according to current and former US officials. This revelation was based on intercepted communications and other intelligence gathered by US agencies.

The reports suggested that Trump's campaign team had multiple contacts with Russian officials, including:

1. Donald Trump Jr., the president's son, who met with a Russian lawyer, Natalia Veselnitskaya, at Trump Tower in June 2016. The meeting was reportedly set up by Emin Agalarov, a Russian pop star and the son of a wealthy Russian developer who had business ties to Trump.
2. Jared Kushner, Trump's son-in-law and a senior advisor, who met with Sergey Kislyak, the Russian ambassador to the US, at Trump Tower in December 2016.
3. Michael Flynn, Trump's national security advisor, who had multiple contacts with Russian officials, including Kislyak, during the transition period.

The Trump administration initially denied any wrongdoing, but subsequent investigations and testimony from former officials have revealed a more extensive pattern of contacts between Trump's team and Russian officials.

In July 2018, the Senate Intelligence Committee released a report concluding that the Russian government had engaged in a "sweeping and systematic" effort to interfere in the 2016 election, and that Trump's campaign had been aware of and potentially benefited from these efforts.

In March 2019, Special Counsel Robert Mueller's report concluded that there was no evidence of a conspiracy between the Trump campaign and Russia, but it did not exonerate Trump of obstruction of justice. The report also highlighted numerous contacts between Trump's team and Russian officials, including the Trump Tower meeting and Flynn's conversations with Kislyak.

The controversy surrounding Trump's campaign contacts with Russian officials has led to numerous investigations, including the Mueller investigation, and has sparked intense debate about the nature of the relationship between the Trump campaign and Russia.