2 Chronicles Family

In 2 Chronicles, bloodlines are all-important. God lets everyone know that David and descendants will be the only people to rule over Israel, no matter how bad they are at the governing (we're looking at you, Rehoboam). God also has a special relationship with his people because he's made a pact with their ancestors that he considers unbreakable. Because of this, he gives them a pass for some pretty terrible behavior just because they're members of the tribe.

Questions About Family

1. Why does God decide to go all in with David's family? Does the fact that King Zedekiah is the last king from David's line mean that God broke this promise?
2. How are the people of Israel and Judah linked through family ties? We bet tensions were high at those holiday gatherings.
3. What's the benefit or harm in having Judah's rulership determined by family descent rather than merit? Does "Because God said so" cut it as an explanation?