19 March 2018

Threshold – FOI examines what this buzzword means

The term threshold often appears in current defence policy documents – although usually without any explanation of what it means. An FOI report investigates what lies behind the concept.


Combat Vehicle 90 and Tank 122 advance across a training area during a battle exercise on Gotland. Sweden’s stationing of military forces on Gotland has a deterrent effect on an aggressor. Photo: Bezav Mahmod/Armed Forces.

Threshold has become something of a fashionable concept in the defence sector. It is used in the Swedish parliament’s defence bills, and in the defence ministry’s military-strategic doctrine and perspective planning; it may even be mentioned several times in the same text, but to mean different things.

“It’s often used in serious contexts. But it’s difficult to put one’s finger on exactly what is intended in these policy documents. I’ve looked for an explanation, but haven’t found one,” says Robert Dalsjö, deputy research director at FOI.

The problem is that many use the concept, while they interpret it differently. At the same time, raising the threshold capability of Swedish defence is a political objective.

“If one discusses measures for increasing Swedish threshold capability, then one must know what the intention is. This has implications for the type of national defence one gets,” he says.

In the report, “Fem dimensioner av tröskelförsvar [Five dimensions of a threshold defence],” which was presented at the end of last year, he explores what the concept can mean. The report is summarized in a memo, The Six Functions of a Threshold – An Attempt at Conceptual Analysis.

Five meanings

“My opinion is that threshold has two main meanings: deterrence and defence,” says Robert Dalsjö.

He explains with a few examples.

  • Sweden’s military contingent on Gotland, for example, has a deterrent effect. An aggressor that nevertheless invades the island will end up in a war with Sweden.
  • Defence: this deals with what happens if deterrence fails – that an aggressor has to accept that there are Swedish tanks on the island when it is calculating what forces it needs for an invasion.

The concept can have three additional connotations, as a marker, tripwire, and alarm bell, according to Robert Dalsjö. These reinforce deterrence or defence.

  • Marker: the intent is to signal that Sweden will not yield if, for example, another power tries to frighten away Swedish aircraft from international airspace.
  • Tripwire: is an international term that implies that a third country can be drawn into a conflict. If Russia, for example, were to try to invade Tallinn, it would be met by a tripwire contingent, a British NATO battalion in which French and Danish soldiers participate.
  • Alarm bell: indicates that an attack has begun. This could be, for example, a Swedish warship situated far from the Swedish mainland. An aggressor would have to sink the ship early on, and thereby start the war.

“It deals with characteristics or capabilities on the defender’s part that can influence an aggressor’s decisions,” says Robert Dalsjö.