WASHINGTON - Known for acting on impulse, President Donald Trump has adopted an uncharacteristically go-slow approach over whether to hold Iran responsible for attacks on Saudi oil facilities, showing little enthusiasm for confrontation as he seeks re-election next year.After state-owned Saudi Aramco's plants were struck on Saturday, Trump did not wait long to fire off a tweet that the United States was "locked and loaded" to respond, and Secretary of State Mike Pompeo blamed Iran.But four days later, Trump has no timetable for action. Instead, he wants to wait and see the results of investigations into what happened and is sending Pompeo to consult counterparts in Saudi Arabia and the United Arab Emirates this week."There's plenty of time," Trump told reporters on Monday. "You know, there's no rush. We'll all be here a long time. There's no rush."Two U.S. officials told Reuters on Tuesday that Washington believes the attack was launched from Iran, with one of them saying it originated in Iran's southwest.U.S. officials say Trump, who is famously skeptical of his intelligence community, wants to ensure the culprit is positively identified in a way that will pass muster not only with him but with the American people."In responding to the greatest attack on the global oil markets in history, I think not rushing to respond and ensuring everybody is on the same page is where we should be," said a U.S. official, who spoke on condition of anonymity.Trump's stance today is in stark contrast to 2017, less than three months into his presidency, when he waited only two days before launching air strikes to punish Syrian President Bashar al-Assad's forces for a chemical weapons attack.AMERICA FIRSTTrump's caution reflects the "America First" world view that found support with his base in the 2016 presidential campaign and that he is trying to promote again as he seeks a second term in 2020.Pillars of that view are that the Iraq war was a waste of blood and money, that the end of the war in Afghanistan is long overdue, and that Washington should be reimbursed for deployment of U.S. troops abroad, from South Korea to Germany.Jon Alterman, a Middle East expert at the Center for Strategic and International Studies and a former State Department official, said Trump also "has grown increasingly cautious as the reality of any military actions increased.""There’s a large constituency the president has that thinks it would be lunacy to go to war against Iran," he said. "There's a large part of his base that thinks the craziest thing we could do is committing ourselves to endless wars in the Middle East."The attacks on Saudi targets have stymied for now what had been an effort to open talks with Iranian leaders to try to get a sense of whether they were ready to strike a deal on their nuclear and ballistic missile programs in response to economic sanctions that have taken a toll on Iran's economy.Trump's willingness to consider easing sanctions on Iran alarmed his national security adviser, John Bolton, when the president raised the idea at a meeting last Monday, a source close to Bolton said. By the next day, Bolton was out.Bolton's departure removed a central anti-Iran voice from the president's inner circle. A well-known foreign policy hawk, Bolton was said to be furious in June when Trump abruptly called off air strikes in response to Iran's shooting down of a U.S. drone."If Bolton were there, he would be saying it was definitely Iran, and we need to strike right now," said a former senior administration official.Trump rebuked Lindsey Graham, one of his staunchest supporters in the U.S. Senate, after the Republican senator said in a tweet on Tuesday that Iran had seen Trump's response to the drone downing as a sign of weakness."No Lindsey, it was a sign of strength that some people just don’t understand!" Trump said on Twitter.In Venezuela, despite repeated vows that all options were on the table, Trump also resisted Bolton’s suggestions for a stronger focus on military planning in the country, where a U.S.-led campaign of sanctions and diplomatic pressure has failed to push socialist president Nicolas Maduro from power.Barring a major escalation, future U.S. measures are expected to continue to stop short of military action due to a lack of support from U.S. voters but also because of opposition from allies in Latin America."We have to be realistic," a Venezuela opposition source said. "Trump will not be sending in the Marines to rescue us."