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QR 38 Cuban Missile Crisis, 4/26/07 I. Background II. Uncertainty about Soviet type III. Brinksmanship. I. Historical background to crisis. October 1962: US discovered that Soviet Union was installing nuclear missiles (MRBMs) in Cuba
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QR 38Cuban Missile Crisis, 4/26/07I. BackgroundII. Uncertainty about Soviet typeIII. Brinksmanship
I. Historical background to crisis • October 1962: US discovered that Soviet Union was installing nuclear missiles (MRBMs) in Cuba • This represented a significant increase in the risk to the US, because these weapons could reach US soil much faster than ICBMs; and the Soviets only had a couple of ICBMs. • Missiles were probably there to deter US invasion of Cuba
Response of Kennedy administration • JFK did not immediately share the fact that the US had discovered the missiles with the Soviet Union, or make any public announcements • Instead, convened ExComm • ExComm met in secret over about a week to work out appropriate response; know a lot about their deliberations now
Initial Reactions • Initially, understood the choice to be between military action (supported by JCS) and focusing on a purely diplomatic solution (Stevenson) • The immediate risk of doing nothing acceptable, but Kennedy aware that the missile installations could continue and worried about US loss of face in larger Cold War picture
Blockade option • Robert McNamara, Secretary of Defense, came up with the idea of a blockade or “naval quarantine” • This was attractive because it greatly reduced the risk of nuclear war; but JCS continued to resist • Eventually consensus formed around use of blockade
Blockade Imposed • Kennedy announced discovery of missiles and imposition of blockade on October 22, one week after missiles first discovered. • Navy directed to set up blockade closer to Cuba than its usual procedures specified, and to be lenient about letting civilian boats through • In practice, Navy mostly followed SOPs.
Negotiations • Soviets responded to Kennedy’s announcement by looking for ways to end crisis, while publicly hanging tough • Soviet Presidium made early decision not to let crisis escalate to war, but didn’t make this public • Began quietly exploring deal that would get missiles out of Cuba in exchange for US commitment not to invade Cuba, and US Jupiter missiles out of Turkey
Crisis resolution • Soviets ordered ships with military cargo to turn back • Khrushchev sent Kennedy private, conciliatory letter on Oct. 26, am • Later that day publicly sent a tougher letter, adding missile swap to conditions • US agreed but insisted that missile swap be kept secret
II. Uncertainty about Soviet type • This is a game of compellance: The US attempting to compel the Soviets to withdraw • Using threats to accomplish this; but imposing the threat would be costly for both sides. • US uncertain about how hard-line Soviets were; i.e., whether they preferred withdrawal or defiance in face of US threat
Game with uncertainty Withdraw SU 1, -8 Threat Defy US Soviets hard-line (p) -10, -4 No -2, 2 1, -4 Withdraw Nature SU Threat Defy Soviets soft (1-p) -10, -8 US -2, 2 No
Equilibrium • If the Soviets are hard-line, they get a payoff of -8 from withdraw and -4 from defy, so they with defy • So if the US know the Soviets were hard-line, shouldn’t make the threat • If the Soviets are soft, they will withdraw • So if the US knew the Soviets were soft, US should make the threat
Critical value of p • The US expected payoff from threat is p(-10) + (1-p)(1) = 1-11p • US payoff from no threat is -2 • So US should threaten if 1-11p>-2 11p<3 p<3/11 (.27)
US strategy • Can think of .27 as the upper limit of US tolerance for risk • Kennedy’s statements suggest that he thought the probability that the Soviets were hard-line was between .33 and .5 • So too risky for US to use threat of war • The threat is “too big” to be credible
III. Brinksmanship • So, Kennedy turned to alternative strategy, brinksmanship • Brinksmanship is the use of a threat that leaves something to chance; a probabilistic threat • Using brinksmanship involves giving up some freedom of action, i.e. of reducing risk
Modeling brinksmanship • Brinksmanship is the creation and control of risk • US had to create some risk of war; but not too high, or wouldn’t be credible • Model this by introducing a probability, q, with which war will occur if Soviets defy
Payoff with risky threat • US payoff at defy outcome is now -10 (war) with probability q and -2 (same as doing nothing) with probability 1-q • So expected US payoff is -10q+(1-q)(-2) = -2-8q • Soviet hard-line payoff is -4(q)+2(1-q) = 2-6q • Soviet soft payoff is -8(q)+2(1-q)=2-10q
Brinksmanship game Withdraw SU 1, -8 Brink Defy US Soviets hard-line (p) -2-8q, 2-6q No -2, 2 1, -4 Withdraw Nature SU Brink Defy Soviets soft (1-p) -2-8q, 2-10q US -2, 2 No
Soviet strategy • What value of q will compel the Soviets to withdraw? • If hard-line, need -8>2-6q 6q>10, q>1; can’t satisfy • So US can’t compel hard-line to withdraw by using brinksmanship
Soviet strategy • If Soviets are soft, will withdraw if -4>2-10q 10q>6 q>.6 • So US could induce soft Soviets to withdraw by setting q above .6 • This is the effectiveness condition
US strategy • What is the critical value of q that will lead the US to use brinksmanship? • That will depend on p • Expected value of making the threat is p(-2-8q)+(1-p)(1) = -8pq-3p+1 • So should make the threat if -8pq-3p+1>-2 • q<3/8((1-p)/p) • This is the acceptability condition
Results • When p<.27, q=1 is in the acceptability zone, so a full threat can work. • When .27<p<.38, full threat not acceptable (need q<1), but there is a range between .6<q<1 that can work • So some scope for brinksmanship
Brinksmanship in practice • In the crisis, the US blockade created the risk of war and so worked as a brinksmanship strategy • Because Kennedy didn’t know the precise values of p and q, began with small threats (very low value of q) and gradually increased until the Soviets backed down • This did, though, run some risk of nuclear war
When can brinksmanship work • For brinksmanship to work, need to be able to satisfy both the effectiveness and acceptability conditions • If q too low, won’t be effective • If q too high, US won’t be willing to bear the risk • Capture these considerations in a graph