While Wall Street appears to have ignored the latest political spat within the Republican party over the weekend, in which Donald Trump lashed out at outgoing Senator Bob Corker, while the latter compared the White House to "daycare for adults", and later warned Trump may launch World War III, this particular feud involving the president may last longer than just the usual 24-hour news cycle, and could have dire consequences for the market, which in recent days has repriced a more than 60% probability (according to Goldman) that Trump's tax reform will pass.

Well, according to Cowen analyst Chris Krueger, not so fast.

In a note released this morning, Krueger writes that "tax euphoria may break this week, with the Senate budget back to zero-margin on vote as President Trump, Sen. Bob Corker feud." And without a budget, "tax is dead. Full stop," Krueger writes.

Cowen now sees the margin for passing a budget in the Senate as more challenging than in the House, plus "radically different" documents will have to be merged and passed again.

Passing FY 2018 Senate budget has "some eerie parallels" to health care, as no Democrats will vote for the budget; Sen. Rand Paul is expected to vote no because it doesn’t cut spending fast enough; Sen. John McCain also sounds like a no as it doesn’t repeal sequester, which disproportionately hits the Pentagon.

That means GOP can only afford one more defection, with Corker, a deficit hawk, engaging in "one of the more surreal public correspondence exchanges in recent memory" days after saying Secretary of State Rex Tillerson, Defense Secretary Jim Mattis and White House Chief of Staff John Kelly help keep U.S. from chaos.

"Either Trump realizes that Corker can sink the remainder of the Trump/GOP legislative effort and is upset by that reality, or he didn’t/doesn’t know and just made it a reality. Either way, we see ZERO upside for the budget process/tax reform in this Twitter tantrum with the policy downside limit-down"

Maybe not: because in the premarket on Monday, bank stocks sensitive to potential tax cuts, are once again rising, suggesting all is well: JPMorgan up 0.3%, BofA +0.3%, Morgan Stanley +0.8%. Or perhaps this is just one more example of a market that is now so bored with incremental news flow which has zero impact on risk assets, that it is simply yet another "shock which no longer shocks." Then again, as so many Wall Street analysts have warned, it is only a matter of time before one shock does finally shock the S&P, unleashing the spire of shocks, built of over years and years of non-resolution, and merely swept away under the rug with trillions in central bank liquidity injections.

Stated simpler, if indeed Trump tax reform is dead - again - a sharp market turnaround may be imminent.