Sen. Jeff Flake, R-Ariz., grabbed headlines all week saying his party was in deep trouble.

Republicans, he said, have become a "coarser party." They are in "denial" about President Trump. The best thing a Republican-controlled Congress could do at this point is "adjournment."

Flake actually said that last bit in 2006, shortly before the Democrats retook both houses of Congress. "I think Republicans have by and large gone native. I don't know how you can conclude otherwise," he told Reason, a libertarian magazine. "You look at any measure of spending — overall spending, mandatory, discretionary, non-defense discretionary, non-homeland security spending — whichever way you slice it, the record looks pretty bad."

Back then, Flake wasn't a senator but a lowly House member. He had been kicked off the House Judiciary Committee for what then Speaker John Boehner described as verbal attacks on Republican leaders. The attacks in question appear to have been a criticism of the secrecy surrounding earmarks.

"The vast majority of them we have no idea," Flake told "60 Minutes" correspondent Morley Safer. "Sometimes, you'll see a press release when somebody's taking a victory lap. Some of them don't want anyone to know ever that they got that earmark, other than the lobbyist that they got it for."

That was over 10 years ago. Now Flake is back with a new book whose title, Conscience of a Conservative, is borrowed from the 1960 Barry Goldwater classic. (Much to the consternation of the Goldwater ghost writer's son, longtime movement conservative Brent Bozell.)

Give Flake points for consistency: he is a rare Republican who has called out his party's excesses under both the George W. Bush and Donald Trump presidencies. Sen. Mike Lee, R-Utah, and Rep. Justin Amash, R-Mich., would likely have been equally critical of both presidents, but neither were on Capitol Hill in the Bush years.

Vice President Mike Pence was one of the leading GOP opponents of Bush-era big government, opposing both No Child Left Behind and the deficit-financed Medicare prescription-drug benefit. He is naturally a Trump loyalist now. The ranks of "Never Trump" were disproportionately, though hardly exclusively, filled with conservatives who thought the Bush years were wonderful.

A more cynical observer, however, might say that Flake is consistent in another way: kicking his party while it is down. He has a strong record as a fiscal conservative regardless of who is in office. But his two big declarations of independence occurred when the GOP was at low points in terms of popularity.

If this is an attempt by Flake to avoid the same fate ahead of an election year, the early results aren't encouraging. Flake's poll numbers aren't good. Liberals won't give him much credit for writing an anti-Trump book while voting to partially repeal Obamacare. Partisan Republicans will wonder why Flake, who has long clashed with Arizona conservatives over immigration, isn't standing with the president.

So, let's deal with Flake's arguments on the merits. In his book, he draws a straight line from the last period of unified Republican control of the federal government he disliked to the current one.

"When we couldn't argue that we were the party of limited government anymore, then that forced us into issues like flag burning or trying to intervene in the Terri Schiavo case, things that we wouldn't have done otherwise if we would have been arguing about true principles of limited government or spending," Flake told NPR.

Flag burning actually peaked as an issue under George H.W. Bush, not his son, though Trump tried to revive it (not very successfully, on the Hill at least). But Flake is right that Bush 43's grassroots supporters engaged in a lot of red-state identity politics in the 2000s, even if the president seldom participated himself. In 2008, Sarah Palin became a conservative folk hero for reasons that had more to do with cultural identity than policy or philosophy.

Bush and Sen. John McCain were reluctant to whip up these passions, even as they each benefited from them. Trump had no such compunctions. His entire pitch to the Republican base was one of cultural solidarity and opposition to liberal elites, as he had even less grounding in limited government or principled social conservatism than Bush, McCain, or Mitt Romney.

Trump most famously embraced (and only belatedly discarded) conspiracy theories about former President Barack Obama's birthplace, for which he is hammered at length in Flake's third chapter — at some political risk to the senator, given the popularity of birtherism in a few Arizona conservative corners. The restraint of Bush, McCain, and Romney in the face of Democratic wins was dismissed by some base voters as a craven desire to be "good losers," while Trump seemingly sought victory at all costs.

Flake points out that victory at all costs comes at, well, a cost. "We took the road too often traveled — of venality and mendacity and political expediency," he writes. And in the case of Trump, 2016 may yet prove a Pyrrhic victory for Republicans.

Nevertheless, there are also ways in which Trumpism (as distinct from the president himself) has at least arguably been more conservative than Bushism, or even some of what Flake espouses. Trump's budgets, even with their mathematical challenges, are tougher on non-defense discretionary spending than Bush's ever were, and his budget director Mick Mulvaney is a Freedom Caucus alumnus.

Compare some of Trump's "America First" pronouncements with Bush's second inaugural address talk of lighting fires in the minds of men. Neither vision is perfect, but which more closely comports with conservative realism and an appreciation of the limits of what our government can accomplish in a fallen world?

On immigration, Bush's compassionate rhetoric compares favorably to Trump's often caustic tone. But here too, an appreciation of limits — along with an acknowledgement that assimilation has both inherit civic value and important implications for Republican political prospects — might incline a conservative in the opposite direction of Bush and Flake's policy preferences.

Perhaps the biggest dilemma for conservatives is that both Bush and Trump demonstrate the weakness of the constituency for limited government, even inside the Republican Party. Bush revealed it when he had to create the biggest new entitlement since Lyndon Johnson and accede to sizable increases in domestic discretionary spending to win re-election, followed by the failure of his free-market Social Security reforms to catch on with a GOP-controlled Congress.

Trump showed how little appetite there was for these kinds of reforms even among a relatively conservative Republican primary electorate. Outside of attacking regulations, he also did much less during the primaries to reassure those who wanted to cut government than social conservatives or Second Amendment activists, perhaps suggesting he knew which voting blocs were big enough to potentially deny him the nomination.

Flake astutely points out his party's abandonment of Goldwater-style limited government and William Buckley Jr.'s view of conservatism as the "politics of reality." But he doesn't prescribe much of a solution for the fact that the former has been partly a recognition of political reality.

"We must be willing to risk our careers to save our principles," Flake writes. More Republicans would be principled if it were less risky.