You need to forget that Michael Shannon and Kevin Spacey look nothing like the original figures they are portraying. What Spacey lacks in the actual President's physical stature he makes up in his voice and mannerisms, whereas I found Shannon's Presley voice more lightweight than I'd have expected though, it must be said, there is very little of the King's everyday speaking voice recorded for posterity, apart from that in his film acting roles.
Having got over these hurdles, I found this a reasonably entertaining film, improving as it went along.
It centres on Elvis' wish to meet with the President in 1970 in order to offer his 'services' as an undercover agent(!) to assist with the fight against drugs which he sees as part of an endemic wholesale corruption of the young. When Nixon first hears of the attempt to meet him he laughs it off, showing no interest at all, but then it's put to him that it could be played to political advantage. So Presley's persistence eventually pays off with a reluctant President allowing him an audience of five minutes max.
One of the things we surmise about the meeting (no records were kept) was that it lasted significantly longer. The absence of any record of the conversation between the two men allows the film's storytellers to create a scenario in which the singer wins the politician over, and achieves - though there's considerable doubt about it - most of his desire. This is a fiction rather than an attempt at historical accuracy, and we can go along with that.
We see little of Nixon in the film's first half - he features in a brief opening scene. The remainder of this under-90 minute film is all about the meeting, the humour arising from Elvis' ignoring or forgetting to observe the instructions of dos-and-don'ts on acceptable behaviour given to him before being ushered into the Oval Office, and then Nixon being confused and put out by his guest's bold conduct, together with his own gaucheness regarding social etiquette in a situation outside his experience.
Both stars do well with the material they are given, which is quite strong. It's a pleasant little diversion, hardly earth-shattering, but director Liza Johnson hadn't intended that it should be.
A fair recommendation........................6.
49 minutes ago