This evening, President Barack Obama will appear before Congress to deliver the first State of the Union address of his second term, outlining an agenda and the likely Washington battle lines for the coming four years. But thus far that agenda has been fairly inchoate, limited to a muscular inaugural address that affirmed basic progressive principles but said less about the president's legislative plans. And while Tuesday's speech will largely focus on middle-class pocketbook issues, Obama could ultimately choose to circumvent Capitol Hill gridlock by turning his energies toward foreign affairs, as Ronald Reagan did in negotiating with Mikhail Gorbachev and Bill Clinton did in seeking to broker Middle East peace.

Lined up across from Obama to deliver the Republican response is Sen. Marco Rubio. Despite his relative inexperience -- Rubio came out of nowhere to win his seat in 2010 -- the junior senator from Florida is a constant presence on the short list for 2016 GOP presidential candidates. So if Rubio is destined to deliver the rejoinder to Obama's opening salvo, what can the American public expect? Has the Cuban-American begun to articulate a Rubio doctrine? Here is what we know so far about his worldview.

• American engagement: When it comes to the current Republican foreign-policy camps, Rubio aligns himself far more with the party's interventionist wing, supporting military intervention in Libya and urging stronger American action in support of Syrian rebels. In a foreign policy address at the Brookings Institution, Rubio spoke of a post-war order shaped by American engagement with the world, a tradition the country would be well-served not to abandon but renew: "So yes, global problems do require international coalitions," he explained. "On that point this administration is correct. But effective international coalitions don't form themselves. They need to be instigated and led, and more often than not, they can only be instigated and led by us." Rubio's decision to affiliate himself with the GOP's internationalist wing has struck many observers as surprising, given the senator's ascent as a prodigy of the by-and-large isolationist Tea Party movement. But the shift also places him in agreement with his party's foreign-policy elders.

• Syria: The slow-burning conflict in Syria, where two years of violence has left 60,000 dead, has become one of the hardest tests of American foreign-policy thinking today. Critics have seized on the Obama administration's cautious approach as evidence of a weak-willed foreign policy. Here, Rubio has articulated a moderately hawkish approach, writing in the Wall Street Journal that "diplomacy doesn't stand a chance in Syria unless the military balance tips against Assad.... [T]he U.S. should make clear that we stand ready to step in and fill key gaps between the rebels' military needs and our allies' capabilities. Empowering and supporting Syria's opposition today will give us our best chance of influencing it tomorrow, to ensure that revenge killings are rare in a post-Assad Syria and that a new government follows a moderate foreign policy." While repudiating Tea Party isolationism, the position also strays from Bush-era neoconservatism while continuing to see the exercise of military power as central to U.S. influence abroad.

• Iran: In his Brookings address, Rubio expressed a surprising willingness to entertain negotiations on Iran's nuclear program. "We should be open to negotiations with Iran," he argued. "But always remember that they should not be deemed a success when they only lead to further negotiations." Still, he warned, "Stronger pressure shouldn't be postponed in the expectation our forbearance will encourage Iran to act in good faith." One should note, however, that Rubio has also expressed a willingness to carry out a unilateral strike against Iran's nuclear facilities.

• Latin America: In a Los Angeles Times op-ed that accompanied his Brookings address, Rubio argued that the United States must not neglect its neighbors to the south, even as it pivots toward the Pacific and deals with burning crises in the Middle East. "An energy alliance made up of the U.S., Canada, Mexico, Colombia, Brazil and a post-Chavez Venezuela" would, Rubio argued, help establish a "a democratic, peaceful and stable alternative to the Middle East in global energy production." And where democratic progress in the region has stalled, Rubio urged the United States to take a more active role. "We also need to assist Latin America's many fledgling democracies," he wrote. "Free elections are crucial, but they aren't enough to secure a democracy.... Sadly, too many Latin American nations seem to have forgotten their own struggles against authoritarian regimes." Finally, trade agreements and continued security cooperation would form the bedrock upon which to build a renewed U.S. foreign policy vis-à-vis Latin America. On their own, the positions Rubio stakes out on Latin America are unremarkable and boilerplate, but it is worth noting as a statement of priorities that he chose to devote the op-ed that accompanied the most significant foreign-policy address of his career to Latin America, which has become during the past decade a backwater of the foreign-policy establishment.

• China: In the midst of the Republican presidential campaign, China emerged as a favored villain of Mitt Romney, who vowed to brand the country a currency manipulator on his first day in office. But in October, Rubio broke with the prevailing orthodoxy and told Bloomberg that he thought that approach was a mistake, saying that "[i]t could kick off a trade war that would be bad for the economy" and that he agreed with Obama's position on the issue.

• Foreign aid: In what might have come as a shock to his deficit hawk political backers, Rubio came out in favor of foreign aid at Brookings. "Faced with historic deficits and a dangerous national debt, there has been increasing talk of reducing our foreign aid budget," the senator noted. "But we need to remember that these international coalitions that we have the opportunity to lead are not just military ones, they can also be humanitarian ones. In every region of the world, we should always search for ways to use U.S. aid and humanitarian assistance to strengthen our influence, the effectiveness of our leadership, and the service of our interests and ideals."

• Immigration: While not a cut-and-dry foreign policy issue, immigration reform is a question near and dear to Rubio, who has become the GOP's point person on moving a reform package through the Senate. As a descendant of Cuban-American exiles, Rubio is a beneficiary of the notoriously lenient immigration rules for Cubans. As a result, many in the American Latino community view Rubio with distrust -- as a member of a privileged ethnic group with access to rights not available to other Latino immigrants. In the Senate, Rubio is pushing for a path to citizenship for undocumented immigrants, a group his mother calls los pobrecitos (the poor ones), but the exact details of the package have yet to be hammered out. "I have to balance that humanity with reality," Rubio told Time. "We have immigration laws. They have to be followed. But yeah, [my mother] reminded me that there's a human element to this as well. As a policymaker, you have to strike a balance." Whether the package gains approval is still anyone's guess, and an amnesty provision -- which Tea Party supporters view as anathema -- is politically fraught for Rubio.

If any doubt remains about the political upside to rolling out Rubio tonight, consider this: the Florida senator will deliver his State of the Union response in both English and Spanish. On the heels of the GOP's crushing loss of the Hispanic vote, the political symbolism is clear. But even if Rubio doesn't mind being trotted out as a political mascot for a night of political theater, his foreign-policy views make clear that he's something of a wild card in the Republican Party -- one who has moved away from his far-right origins as a Tea Party darling.