Legally speaking, there is no such thing as "treason against the government". Any legal charge of treason is treason against the country. Article III, Section 3, Clause 1 of the US constitution reads:
Treason against the United States, shall consist only in levying War against them, or in adhering to their Enemies, giving them Aid and Comfort. No Person shall be convicted of Treason unless on the testimony of two Witnesses to the same overt Act, or on Confession in open Court.
See also 18 U.S. Code § 2381 - Treason which reads:
Whoever, owing allegiance to the United States, levies war against them or adheres to their enemies, giving them aid and comfort within the United States or elsewhere, is guilty of treason and shall suffer death, or shall be imprisoned not less than five years and fined under this title but not less than $10,000; and shall be incapable of holding any office under the United States.
It is hard to see how making war on the United States, or helping an open enemy do so, could "save the nation" and in the absence of either of these, there is no treason, although other charges might possibly apply.
The interactive Constitution site from the National Constitutions Center says about this provision of the Constitution:
Treason is a unique offense in our constitutional order—the only crime expressly defined by the Constitution, and applying only to Americans who have betrayed the allegiance they are presumed to owe the United States. While the Constitution’s Framers shared the centuries-old view that all citizens owed a duty of loyalty to their home nation, they included the Treason Clause not so much to underscore the seriousness of such a betrayal, but to guard against the historic use of treason prosecutions by repressive governments to silence otherwise legitimate political opposition. Debate surrounding the Clause at the Constitutional Convention thus focused on ways to narrowly define the offense, and to protect against false or flimsy prosecutions.
The Constitution specifically identifies what constitutes treason against the United States and, importantly, limits the offense of treason to only two types of conduct: (1) “levying war” against the United States; or (2) “adhering to [the] enemies [of the United States], giving them aid and comfort.” Although there have not been many treason prosecutions in American history—indeed, only one person has been indicted for treason since 1954—the Supreme Court has had occasion to further define what each type of treason entails.
The offense of “levying war” against the United States was interpreted narrowly in Ex parte Bollman & Swarthout (1807), a case stemming from the infamous alleged plot led by former Vice President Aaron Burr to overthrow the American government in New Orleans. The Supreme Court dismissed charges of treason that had been brought against two of Burr’s associates—Bollman and Swarthout—on the grounds that their alleged conduct did not constitute levying war against the United States within the meaning of the Treason Clause. It was not enough, Chief Justice John Marshall’s opinion emphasized, merely to conspire “to subvert by force the government of our country” by recruiting troops, procuring maps, and drawing up plans. Conspiring to levy war was distinct from actually levying war. Rather, a person could be convicted of treason for levying war only if there was an “actual assemblage of men for the purpose of executing a treasonable design.” In so holding, the Court sharply confined the scope of the offense of treason by levying war against the United States.
The Court construed the other treason offense authorized by the Constitution similarly narrowly in Cramer v. United States (1945). That case involved another infamous incident in American history: the Nazi Saboteur Affair. Cramer was prosecuted for treason for allegedly helping German soldiers who had surreptitiously infiltrated American soil during World War II. In reviewing Cramer’s treason conviction, the Court explained that a person could be convicted of treason only if he or she adhered to an enemy and gave that enemy “aid and comfort.” As the Court explained:
A citizen intellectually or emotionally may favor the enemy and harbor sympathies or convictions disloyal to this country’s policy or interest, but, so long as he commits no act of aid and comfort to the enemy, there is no treason. On the other hand, a citizen may take actions which do aid and comfort the enemy—making a speech critical of the government or opposing its measures, profiteering, striking in defense plants or essential work, and the hundred other things which impair our cohesion and diminish our strength—but if there is no adherence to the enemy in this, if there is no intent to betray, there is no treason.
In other words, the Constitution requires both concrete action and an intent to betray the nation before a citizen can be convicted of treason; expressing traitorous thoughts or intentions alone does not suffice.