Image copyright Getty Images

A week that began with a reset ended with Russia, the scandal that refuses to go away.

On Tuesday night, when Donald Trump delivered his first speech before a joint session of Congress, there was a new tone, in marked contrast to the shrillness of his American carnage inaugural, and even new tailoring, a more sleekly fitted suit.

His Twitter feed, that angry scream of consciousness, had also been unusually quiet.

"THANK YOU!" he wrote in caps on Wednesday morning, after his speech received admiring reviews not just from Republicans but some Democratic pundits as well.

Then on Wednesday night, after a day of unusually flattering coverage, came the triple whammy of stories from the New York Times, the Washington Post and the Wall Street Journal: Russia, Russia, Russia.

His Attorney General Jeff Sessions, America's top law enforcement official, was accused of lying to Congress when he denied having any communications with the Russians.

Image copyright Getty Images Image caption House Speaker Paul Ryan's (right) party controls both chambers of Congress and the presidency

At the precise moment some White House officials hoped to have stabilised the Trump presidency after a wobbly start, the Russian revelations again had a destabilising effect.

Now it has emerged that five Trump advisers, including the president's son-in-law, Jared Kushner, interacted with the Russian ambassador, Sergei Kislyak.

Tuesday night's speech put the Republican leadership on Capitol Hill more firmly behind Trump. A delighted House Speaker Paul Ryan called it a "home run".

The Senate Majority leader Mitch McConnell declared that Trump had become "presidential", especially in that emotional moment when he paid tribute to Carryn Owens, the widow of the Navy SEAL killed in a raid in Yemen.

But in response to the Russian revelations, one senses a certain tension between their partisan and patriotic instincts.

The Republican partisan voice says this is a historic conservative moment.

Rarely is such power wielded.

Image copyright Getty Images Image caption US Attorney General Jeff Sessions (R) has faced calls to step down

Indeed, only two of the last five Republican presidents have addressed a joint session of Congress in which the GOP (Grand Old Party) held majorities in the House of Representatives and the Senate.

Ronald Reagan never got that privilege. Nor did Richard Nixon.

This, then, is a rare opportunity to do big things, like enact tax reform, and dismantle big things, such as Obamacare.

But the Republican patriotic voice expresses nagging concerns that Russia, America's great post-war adversary, could have subverted US democracy and that requires investigation. The Kremlin's nefarious activities have to be exposed.

This conflict between the partisan and patriotic explains their somewhat half-hearted approach to the investigation.

Four Republican-controlled congressional committees could end up looking into the Kremlin's alleged meddling, but the Republican leadership has dismissed calls from the Democrats to appoint a special prosecutor, an independent counsel over whom they would have little control.

Image caption Schumer responded back "Happily talk re: my contact w Mr. Putin & his associates, took place in '03 in full view of press & public under oath. Would you &your team?"

Scandal is the highest form of entertainment that Washington has to offer. Nothing arouses this sleepy city quite like the whiff of political blood. And it is unusual to experience this kind of agitated atmosphere so early in an administration.

Historically speaking, major scandals tend to erupt in the second term of a presidency.

Watergate, which led to Nixon's resignation. Iran-contra, which plagued Ronald Reagan. Monica Lewinsky, which led to Bill Clinton's impeachment.

The Russian allegations have not reached that fever pitch. But this is only the second month of Trump presidency, and already he has lost his national security advisor, Michael Flynn, and seen his Attorney General face calls to resign.

This scandal is also following familiar patterns. The drip, drip, drip of damning revelations. The sense that key Trump aides have tried to conceal the extent of their contacts with the Russians, which points to a cover-up.

Michael Flynn misled Vice-President Mike Pence about his contacts with the Russian ambassador, which led to his resignation. Jeff Sessions misled Congress, which led to calls for him to go. Jared Kushner did not volunteer the information that he met the Russian ambassador during the presidential transition. The press revealed it.

It's often the cover-up rather than the alleged crime, misdemeanour or mistake that causes the most political and personal damage.

Donald Trump is clearly irked by the allegation that he won the presidential election with a Russian assist. And so the week ends with a return of his angry Twitter voice.

Posted on his Twitter feed is a picture of the Senate minority leader Chuck Schumer enjoying what looks like coffee and a donut with the Russian president Vladimir Putin, along with a call for an immediate investigation.

From the reset to Russia in 140 characters.