The low-boil conflict between Israel and Iran has shaped the Middle East for decades. Of the many conflicts that have roiled the region, theirs has long been among the most explosive. The two have attacked each other — mostly quietly and in Iran’s case often by proxy — while avoiding an escalation into direct war.

Israeli officials tell Axios Israel will launch a "significant retaliation" to Iran's massive missile attack within days.

The Middle East moved closer to a long-feared regional war the day after Iran fired a barrage of missiles at Israel and Israel said it began limited ground incursions into Lebanon targeting the Iran-backed Hezbollah militia.

As missile strikes between Israel and Iran continue to make global headlines, more than 400 Wyoming National Guard soldiers and airmen continue

With Israel poised to attack Iran, having already blindsided friends and foes alike with its blitz against Lebanon's Hezbollah movement, all the talk is of an inexorable slide towards a new, pan-Middle Eastern war.

Israel is less likely to hit the oil facilities that underpin Iran's economy or its nuclear sites, according to many of the experts interviewed, who include more than half a dozen former military, intelligence and diplomatic officials from the United States and Middle East.

As Israel continues its ongoing war in Gaza and its offensive against Hezbollah in Lebanon, the Middle East continues to await Israel's vowed response to Iran's recent ballistic missile attack. NBC News' Matt Bradley reports from Beirut and breaks down the events leading to the strong possibility of Israel striking Iran.