It has been years since President Franklin Delano Roosevelt (Bill Murray) has seen Margaret “Daisy” Suckley (Laura Linney).

His “fifth or sixth cousin — depends on how you count” gets brought to his country retreat in upstate New York, and together they sip tea, look at stamps and exchange small talk.

No one will confuse the opening scene of “Hyde Park on Hudson” for “Raiders of the Lost Ark,” despite the similar era. This biography about the couple’s affair takes a long, long time to gather any momentum. When it finally does, it offers some amusing moments of culture-clash humor.

But the film misses a choice opportunity to build a central story around its secondary one: a visit from the King of England (Samuel West) — the first-ever journey to the United States for a sitting English monarch. Roosevelt hopes the meeting will boost American support for the Allies with the start of World War II mere months away.

But “Hyde Park on Hudson” often finds this epic historic event a distraction to its real story about a plain-Jane spinster carrying on a lukewarm romance with a horny middle-aged man.

“He said I helped him forget the weight of the world,” says Daisy, played with little flair by the customarily stellar Linney.

Even with the implied intimacy, the polio-afflicted FDR seems to merely enjoy her earthy company. But then again, he surrounds himself with women, from his dutiful secretary (Elizabeth Marvel) to his headstrong wife (Olivia Williams). Could he be sleeping with all three … or more?

That raucous keystone is what probably drew Murray to the story. Despite looking nothing like the 32nd president, the comedian gamely tackles the part with an admirable amount of restraint — enough to earn him a Golden Globe nomination (whatever that means). An Oscar nod may not be such a lock, though, because director Roger Michell (“Morning Glory”) extracts a spark from his leading man only in episodic chunks.

Instead, the movie relies on Daisy’s dull perspective to connect the action.

It’s a weak choice by playwright Richard Nelson, whose foray into screenwriting embraces one of its most misused tools: narration.

“Inside, everyone was on their very best behavior,” Daisy’s disembodied voice explains prior to a media event for the king.

Showing images (inventively shot by cinematographer Lol Crawley) of the staff on their best behavior would have been enough to imply this simple conceit.

Luckily, the movie perks up whenever the royal couple are onscreen — which is a lot. British TV veteran West faces the unenviable task of portraying the same stuttering “Bertie” who was the centerpiece of 2010’s Oscar-winning “The King’s Speech.” He’s terrific, performing the role more wide-eyed and less stately than Colin Firth.

Equally impressive is his wife, fussy Elizabeth (Olivia Colman), aka the Queen Mum. They play off each other well, capturing the dynamic of a longtime married couple with delicate tension and wit.

Had “Hyde Park on Hudson” primarily focused on their dramatic visit with FDR, it would inevitably fall in the shadow of “The King’s Speech.” But it would certainly have resulted in a more intriguing, engaging film.

(At the Glenwood Arts and Cinemark Palace.)