Union address is explicitly mandated in the U.S. Constitution, Article II, Section 3: among the President's enumerated duties, it is required that "he shall from time to time give to Congress information of the Sate of the Union and recommend to their Consideration such measures as he shall judge necessary and expedient."
The applause and reaction during the 2014 State of the Union address was frequently, but not always, partisan. Obviously certain issues appeal to both parties: Obama received bipartisan standing ovations when he discussed issues on which neither party would dare seem less enthusiastic than its rival (economic competition with China, support for Israel, social mobility through hard work). Likewise, at the speech's conclusion, the overwhelming bipartisan standing ovation for the injured Army Ranger, Cory Remsburg, indicates both parties' desire to be seen supporting injured veterans from Iraq and Afghanistan. However, on many political issues where the parties are polarized, the applause was quite obviously politicized: this was most noteworthy in the President's remarks on health care. No Republican could be spotted to stand or applaud for anything related to the Affordable Care Act.
3. In terms of substantive issues that were addressed by President Obama in the 2014 State of the Union address, I would like to focus on three: education, minimum wage, and healthcare. This reflect the basic rough order in which the President addressed these issues in the course of the speech.
Obama made reference to education early: "teacher" was the fifth word of his speech, the first person mentioned in a Whitmanesque catalogue of American workers, while the first sentence of the speech noted that America has its highest graduation rate in "more than three decades." He returned soon to mention a recent College Opportunity Summit, convened to address how to increase access to higher education. Ultimately these quick early mentions were included as part of a larger stated goal of "guaranteeing every child has access to a world-class education." (The phrase "world-class" suggested that Obama was pitching this in light of widely-publicized reports that America's ranking for educational skill and attainment has slipped badly among industrialized nations.) However, Obama mostly had hortatory inspirational rhetoric without many concrete proposals -- to the extent that there were proposals they were mostly couched in terms of how they would not increase government expenditure. He has encouraged "Race for the Top," which is a Federal initiative to encourage and provide incentive to individual states to improve educational performance: but a President can do nothing concrete about education on the state level apart from provide encouragement and incentives. He emphasized that early education was one of the "best investments" America could make, but did not urge Congress to consider any specific legislation: instead he mentioned pulling together a coalition including "business leaders" and "philanthropists" to discuss how early education could be expanded. And he brought up his plan to expand high speed and broadband access for schools -- presumably because education should serve the purpose of making students employable -- and emphasized that the partnership of industry and government had begun to implement this plan "without adding a dime to the deficit."
Obama's remarks on the Minimum Wage seemed like they were intended to be the centerpiece of the speech. Obama managed to segue into discussion of the Minimum Wage from a discussion of wage inequality for women, which got a fairly impassioned response. But then Obama introduced a hipsterish pizza-store employee and a pizza store owner from Minneapolis, and discussed how the owner had given all his employees a raise, as a recognition of the financial hardship attendant on those with service-sector jobs in the present economy. Obama then vowed to "lead by example" by issuing an executive order that affects all federal contractors, in which they had to raise the minimum wage to $10.10 an hour. This was more than a proposal, it was an executive action that Obama is permitted to take: but the point was that he expected others -- specifically "every mayor, governor, and state legislator in America" -- to follow suit. His rhetorical refrain of "Give America a raise" -- which he seemed almost embarrassed about repeating -- looked like it was written in case Obama found himself (inexplicably) faced with an adoring crowd like the ones he met in 2008, such that he could repeat…