WASHINGTON — Tax Day 2009 was the start of the Tea Party protests against Barack Obama’s agenda.

But as we approach April 15, 2021 — even with the tax-filing deadline extended to May 17 — it’s become noticeable just how quiet the conservative grassroots have been during President Biden’s first three months in office.

Part of it is due to the fact that Biden has never been the lightning rod for the right that Obama, Hillary Clinton, Nancy Pelosi and even AOC are.

But another part is the 2020 defeated candidate who decided to stick around: Donald Trump.

In the 21st century, we’ve seen grassroots political movements — whether real, AstroTurf, or activated by cable news — replace defeated presidential candidates and unpopular presidents. (With the previous leadership either politically discredited by the results or voluntarily leaving day-to-day politics, new players rush to fill the vacuum and voters look for signals as to what they should be doing next and how their party can rebrand.)

The anti-war protests during George W. Bush’s presidency blossomed after John Kerry’s loss in 2004.

The Tea Party came alive after John McCain’s defeat in 2008, as well as Bush 43’s exit from the political stage.

And the Women’s March — the day after Trump’s inauguration — came after Hillary Clinton’s 2016 loss.

Sure, conservatives like Marjorie Taylor Greene are raising lots of money.

Also to be sure, there’s always been lots of grassroots energy behind Trump (though that has dissipated after Jan. 6).

But when we’re talking about grassroots movement and energy to bolster a political party and stop the opposition’s agenda, the energy on the right has been largely MIA.

And it’s all taking place in a political environment where Nikki Haley says she won’t run in 2024 if Trump does, as well as where Sen. Rick Scott, the chair of the GOP’s Senate campaign arm, is presenting Trump with a trophy bowl.

6: The number of women who developed rare blood clots after receiving the Johnson & Johnson vaccine, prompting federal health agencies to call for a pause on its use.

5: The number of Democratic pollsters who have signed on to a statement acknowledging “major errors” in 2020 polling.

31,401,163: The number of confirmed cases of coronavirus in the United States, per the most recent data from NBC News and health officials. (That’s 70,733 more than yesterday morning.)

566,645: The number of deaths in the United States from the virus so far, per the most recent data from NBC News. (That’s 548 more than yesterday morning.)

189,692,045: Number of vaccine doses administered in the U.S.

20.3 percent: The share of Americans who are fully vaccinated.

16: The number of days left for Biden to reach his 100-day vaccination goal.

Another school shooting. Another police officer killing a Black man during a traffic stop.

Why aren’t guns and police reform higher on the political agenda?

Here’s another angle to the continuing story of GOP-led state legislatures trying to place more restrictions on access to the ballot: There’s no guarantee that GOP skepticism of mail-in voting will be a permanent feature of every election in the future. After all, it wasn’t before 2020.

Case in point: Florida, where Republicans once dominated in mail voting, particularly with older voters — and where both former President Trump and now-Gov. Ron DeSantis made frequent use of the method.

In fact, as Noah Pransky of NBCLX reminds us, then-Rep. DeSantis had his own ballot rejected in 2016 due to a mismatched signature. (Pransky himself reported on the ballot’s rejection back in 2018.)

Pransky writes:

“When then-Congressman Ron DeSantis cast his mail ballot for Florida’s primary election in 2016, election workers in his hometown flagged the signature as a mismatch.”

“When DeSantis provided the canvassing board a new signature as a backup to the signatures already on-file, they determined that handwriting also had “no similarities” to the signature on DeSantis’ ballot and rejected the vote, according to Flagler County elections officials.”

More: “DeSantis’s public voting history — obtained through public records requests from the St. Johns and Flagler supervisors of elections — shows he regularly took advantage of Florida’s no-excuse absentee option, casting votes by mail in six out of seven elections between March 2016 and August 2020. The only time he voted in-person during that period was at a well-choreographed photo opportunity, when he appeared atop the ballot during his 2018 gubernatorial run.”

“Now, DeSantis is leading the charge in Florida to change how voters obtain a mail ballot, as well as how easily they can drop it off at their local elections offices.”

Still More: “[He] is also advocating a change to voter signature-matching that would order elections officials to use only a voter’s most-recent signature to determine authenticity.”

Former North Carolina Gov. Pat McCrory on Wednesday is expected to announce a bid for the state’s vacated Senate seat next year, and he’ll be joining a potentially crowded GOP field of candidates, NBC’s Leigh Ann Caldwell writes.

The field already includes Rep. Mark Walker, R-N.C., who took a shot at McCrory on Twitter, and it could also include Trump daughter-in-law Lara Trump, as well as Rep. Ted Budd, R-N.C.

Top private law firms are joining forces to form a “SWAT team”-style response to new voting restrictions, NBC’s Jane Timm writes.

The Biden administration is increasingly at odds with Michigan Gov. Gretchen Whitmer over the coronavirus surge in her state.

The NCAA says it won’t hold championship events in states that restrict transgender athletes’ participation in sports.

Ohio Republican Senate candidate Bernie Moreno has cast himself as a big Trump fan. That wasn’t always the case, NBC’s Henry Gomez notes.

Speaking of Trump and GOP candidates, one Republican in Texas is taking an explicitly anti-Trump stance.

Progressive Democrat Charles Booker is mulling a race against Rand Paul.

How much difference would Biden’s proposed new actions on guns actually make?

The New York Times checks in on Andrew Cuomo’s continuing attempts to ride out his scandals.