Yes, he's a liar. He's a politician. All politicians are liars. How about the CIA sex scandal that was suppressed until after the 2012 elections? Who cares? I don't know a single public or private organization that does not experience sex scandals.
As for the rest, think for a minute about what you're saying. How are our borders unsafe to us? (I presume you're talking about the Latin-American states to our south) Do you think an Arab or Persian is going to sneak into Arizona posing as an El Salvadorian? How? Do you think Mexico is in some state of total anarchy where Middle Easterners just get in and walk around without a passport? Mexico is a tighter police state than here. They have mandatory national service there. We have armchair quarterbacks and fat heads with guns. And Latin America would never risk a political backlash from the US. We have F*cked Mexico up militarily too many times in the past two centuries for their government to be so incautious. Islamists get into the US pretty easily through international airports, my friend. They don't need a border to cross.
Syria is in the midst of civil war. ISIS is a weak group that fights in the Middle East with AK-47s, knives and small explosives. We have an air force and a navy! ISIS does not. My city's police department has more affiliated members than ISIS. I think we're safe here from ISIS and Syria. What is the worry about Iran against the US? That they'll develop a nuclear weapon? Do you know what that would take to do? First, we would know about it. Second, a nuclear bomb is enormous and very expensive. Warheads are smaller but very heavy and very difficult to develop and very, very expensive. Oh, and the US has about 10,000 nukes with multiple warheads. So I think it's a safe bet that no one will try to use one on us. Even so, Iran would also need an ICBM platform or long-range bombers or a nuclear sub. The US has all of the above. It doesn't make sense.
Russia is the only real a military threat to the US in the world. They broke international law and invaded Crimea, though the Crimeans (not the Ukrainian government) wanted the Russians there. The US won't do anything to stand up to Russia, because we don't pick on strong countries anymore. We only pick on the weak ones like Syria and Iran.