Many Christians have different views of the nature of Israel in the Last Days. Some believe that Israel has no significance in the scheme of God's plan for humanity and their salvation. They believe that Israel rejected God, and therefore there is no significance to the nation in God's plan. Some Christians believe that we should support Israel no matter what, and that they are God's chosen people, and if we don't support the nation of Israel then we will be cursed.
My view of the subject is this. God chose Israel in the Old Testament to be his chosen people. He led them, gave them the Law and the Commandments, nurtured them, loved them, and called them his own. He also gave them their own land called Israel. During the Old Testament period they sometimes followed Him and sometimes disobeyed them. God sometimes prospered them when they were obedient, and let them be captured and taken away to other countries when they disobeyed. God lost patience with them after a while, and when Jesus their Messiah came many of the Jewish leaders rejected Him. So as Jesus predicted in 70 AD the Romans came and destroyed the temple, conquered Jerusalem, and the Jews were scattered to all parts of the world. In the Old Testament God said in the Last Days that He would bring the Jewish people back to their land, never more to be scattered again. He said that he would protect them and destroy anyone who tried to destroy Israel. He said that armies would surround Israel and seek to destroy them, but that God would destroy them so Israel would be protected.
What role does Israel play in the return of Jesus to the earth and God's purposes for the world and for Christians?
Israel is where Jesus will return on the Mount of Olives. God will establish a 1000 year reign in which Jesus will rule the earth. Peter mentions a new heavens and a new earth being established. I'm assuming that will be after the 1000 year reign. Even though Israel today in many ways is a secular nation, God promised that Israel was His chosen nation, and that the Jews were still His chosen people. Christians are also God's chosen people, but God still has a plan for the Jews. The apostle Paul said that all Israel will be saved. Paul believed that when Jesus came the Jews rejected Him, but that God's plan was that the Jews would some day come to faith in Jesus and be saved. He did not entirely cast out the Jews. God still loves the Jews, that is those who believe in Him. They might not yet believe that Jesus is the Messiah, but God still has a special affinity for them. So God has not rejected them. His hand is still outstretched to them. Yes, he was upset with them when they were scattered them to the nations, but he never forsook them. The Jews were scattered because of their disobedience. But God still had a purpose for them because He still loved them and loves them now.
Should we support Israel unconditionally?
I would say spiritually yes. We should pray and support Israel because God has chosen them for His purpose. Does Israel do everything righteous in the sight of God? No. They do things in their country that are offensive to God. We do things in the US that are offensive to God. God will not bless sin. So we should pray for Israel to turn to God as we also pray for the US to turn to God. I don't believe that Israel is this holy nation that can't do anything wrong. But if God said in His word that He has a purpose for them, then we must believe that and pray for them and support them. Unconditionally? No. Not if they sin. But because of God's will and word we are called to support and pray for them. Israel was God's chosen nation in the Old Testament, and is still His chosen nation to fulfill His purposes. We should support them unconditionally because of God, and not for their sins.
So I pray for Israel. I pray that they will turn theirs hearts back to God. I pray that they will receive a revelation that Jesus is their Messiah. I pray that they will turn away from sin just like I would for anyone else. Israel isn't this perfect holy nation. But God has called them to come back to Him. He brought the Jews from all the nations of the earth back to Israel. He wants them to turn their hearts to Him and not reject Him as in past times. God will fulfill His purposes for Israel because He has willed it. Nothing will stop God's will. He will protect them and keep them until Jesus the Messiah comes back. But the people of Israel must also do what is right in the sight of God to received His blessings. Israel is not immune to God's judgement of sin. He loves them just like He loves all of us, and wants them to turn themselves to Him. He wants Jew and Gentile to turn to Him.