My fourth scenario of 2013...
In 1986, the civil war in Yemen spilled over into Oman. Oman responded by firing mortar rounds into Yemen. The Soviet Union, Yemen's ally, moved ships into the area. The United States has been asked by Oman to move vessels into the area to help stabilize the situation.
Image: CG 24 Reeves (public domain image from https://en.wikipedia.org/wiki/File:E4-CG24Cruising.jpg)